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Hello Dr Sheela and my friends. I am Noor Khairiyah Binti Hasnul Hadi (A21HP0115) from Tangkak, Johor.

In this chapter, I learned the electronic configuration that emphasized the three main rules which are Aufbau principle, Hund's rule and Pauli's Exclusion Principle. The classification of the elements as well as the periodic trends that explained the atomic radius, ionization energy, electronegativity last but not least is the electron affinity.

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Hi Dr Sheela. My name is Nur Anis Syafiqa binti Abdul Rashid (A21HP0132). I come from Kota Tinggi, Johor.

In this class where we learned chapter 1, I am able to recall the information about the principle used to classify the element into it’s group, period and block. I also learned the classification of elements to metal, metalloid and non- metal.

There are 6 trends that happened in periodic table.
1. Atomic size
⁃ Across period from left to right, the size of atom is getting smaller.
⁃ Going down the group, the size of atom is getting bigger.
⁃ Ionic size of cation (losing electron): cation radius is smaller than atomic size
⁃ Ionic size of anion (gaining electron): anion radius is bigger than atomic size

2. Ionization energy (IE)
⁃ Factors affecting IE: nuclear charge (greater nuclear charge, greater IE), shielding effect and atomic size (greater distance from nucleus, decreases IE).
⁃ Go down the group, IE decreases.
⁃ Across the period, IE increases.
⁃ 1st IE < 2nd IE < 3rd IE.

3. Electronegativity
⁃ Down the group, low electronegativity
⁃ Across the period, high electronegativity
⁃ Metals (left of the table), nonmetal (right end of the table) and metalloid (between metal and nonmetal)
⁃ Fluorine (F) has the highest electronegativity.

4. Electron affinity
⁃ High electron affinity, energy is released (an element gains electron).
⁃ Low electron affinity, energy must be supplied (push electron onto the atom).
⁃ More affinity= greater attraction.
⁃ Halogens have the greater affinities, noble gases have 0 affinities.

5. Metallic- nonmetallic
⁃ Metal form basic oxide, nonmetal form acidic, metalloid form amphoteric oxide.
⁃ Across the period, from metal change to metalloid and nonmetal (metallic properties decreases)
⁃ Goes down the group, metallic properties increases.

6. Oxidation state
⁃ Refer to number of group in periodic table.
⁃ Cation with higher ionic charge (more stable) when cations formed from the same element.
⁃ Various oxidation state for transition metals, actinides and lanthanides.
⁃ Goes down the group, oxidation states of less than 2 from that of the number of group (more stable). Example, TI: TI+ > TI3+
⁃ Due to inert pair effect from the 2 inert electrons in s orbital. Example, Pb: Pb2+ > Pb4+

Lastly, the diagonal relationship.
⁃ The atomic size, electronegativity, properties of compounds are similar.

Thank you Dr Sheela for the 1st week :)

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Hi Dr Sheela. My name is Aisyah Binti Nazerii (A21HP0012). I am from Genting Highland pahang.
For this chapter, i learned in the periodic table we can know the size of the atoms by looked at the atomic number. we also can learn about the trend that involve to determine the state of the atoms. the trend that involve which are atomic size, ionization energy, electronegativity, electron affinity, metal non-metal and oxidation state. This topic also have involve 3 rules which are Hund's, Pauli exclusion and Aufbau rules. That's all from me thank you Dr.

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Hi Dr Sheela. My name is Lai Li Yie(A21HP0049), u can call me Lai. I come from Kuching Sarawak.

From this topic, I have learned:
1.) ATOMIC SIZE
-Atomic size decreases when across period bcs of the increasing nuclear charge make the outermost electrons closer to the nuclues.
-Atomic size increase when going down the group bcs of the increasing of shielding effect is greater than increasing of  nuclear charge.

2.) IONIC SIZE
-Ionic size increases when going down the group bcs of additional energy level.
_When across period from left to right, nuclear charge increase, so ionic size decreases.

3.) IONISATION ENERGY
-3rd ionisation energy>2rd ionisation energy> 1st ionisation energy
-Low ionisation energy is required by filled and half filled orbitals

4.) ELECTRONEGATIVITY
-When going down the group , electronegativity decreases,BCS of outermost electron further away from nuclues
-When across the period from left to right, the electronegativity increases bcs of decreasing of atomic size

5.) ELECTRON AFFINITY
-Definisi: Energy required or released when electron is added into an atom in gas form.
-High electron affinity= Energy is released when an element gains electron
-Low electron affinity=Energy that needed when element push away the electron

6.) METALLIC
-When across the period, metal> metalloid > nonmetal

7.) BASICITY OF ELEMENT OF OXIDE
-When across the period, Basic> Amphoteric > Acidic

Thank you Dr

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Hi Dr Sheela, I'm mirza and I'm from Kota Tinggi, Johor Bahru.

From the previous chapter that I have learned in first week, what I can conclude is in Periodic Table there are Groups and Periods. Group is elements in vertical order based on num. of electrons, while period is elements in horizontal order based on highest quantum num (n).

Secondly, I also learned about electronic configuration which is an arrangement of electron in ataom that follows 3 rules which are Aufbau Principle, Pauli's Exclusion Principle and Hund's Rule.

Then I learned about trend properties, consist of atomic size, ionization energy, electron affinity, oxidation states and metallic nonmetallic.

For Groups trend, atomic num. increase, size atom increase. Meanwhile across period, size get smaller as electrons are in the same period but more protons pulling the electrons.

Second trend is ionization energy (IE). The greater nuclear charge, the greater IE. As down the group, the 1st IE decrease because electron further away from nucleus, more shielding effect from inner shell. Across period, IE increase as nuclear charge increase (more proton pull electron).

For electronegativity, down the group, the farther electrons is away from nucleus, more willing to share, thus low electronegativity. Metals are at left of periodic table, let their electrons go easily, Thus low electronegativity, while at the right end are nonmetals. They want more electrons, thus high electronegativity.

For electron affinity, electronegativity increase, electron affinity increase also.

Lastly for metallic-nonmetallic trend, metal will form basic oxide, nonmetal form acidic oxide and metalloid form amphoteric oxide. Metallic properties changes from metal to metalloid and nonmetal across the period.

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Hai Dr Sheela. My name is Nurul fasihah binti Arshad (A21HP0171) from Kulai, Johor dan merupakan alumni Kolej Matrikulasi Johor.

I dont have too many difficulties to understand this topic since i have learned it from matric. But still, i got little confused between electronegativity and electron affinity. I already referred  to slides, but it didnt give much information or maybe it was a basic introduction so that we will learn more about it on the next topic. saya ada juga cari further explanation on google, but still blur.

But, Thank You so much Dr for the first week class. i found it fun to learn this subject on this semester. cant wait to learn more from Dr Sheela <3

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Hi Dr Sheela and all my coursemates. My name is Norsyafiqa Binti Madlan (A21HP0120) and im from Sandakan,Sabah.

From chapter 1,I,ve just learned about the classification of the elements which is metal(electrical and heat conductor),metalloid(does not conduct electric and heat) and non-metal(semiconductor and from amphoteric oxide).In addition, I also learned about electronic configuration that follows 3 rules namely Aufbau Principle, Hund's Rule and Pauli's Exclusion Principle.After that, I also learned about 6 trends which are atomic size, ionization energy, electronegativity, electron affinity, metallic nonmetallic and oxidation state.Lastly, I also know about the diagonal relationship which has similarities between atomic size, electronegativity and other similar properties.

Thank you Dr :)

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Hi Dr Sheela, nama saya Nur Syidah Binti Salim(A21HP0156) dan tinggal di muar johor.

1) Saya agak kurang jelas dengan 2nd IE dan 3rd IE. 'The 2nd IE of Be is lower than 2nd IE of Li since Be has half-filled orbital in 2s but Li has full filled orbital'. Betul ke kalau saya terangkan macam ni? Cukup ke explaination tu atau saya kena tulis tentang faktor lain seperti nuclear charge dan distance?

2) Tentang oxidation state, Bi will be 3+ instead 5+. Can I assume that it will be 3+ due to its electron configuration? Or is there another way to determine the stable oxidation states?

Thank you Dr Sheela <3

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Hi, Dr Sheela. I am Ong Shi Ting (A21HP0181) from Kulim, Kedah.

From this topic, I had learned about :
1. The electronic configuration is followed Aufbau Principle, Hund's Rule and Pauli's Exclusion Principle.

2. Trends that happened in the Periodic Table.
a. Atomic Size
- When going down the group, the size of atom is getting bigger.
- When across the period, the size of atom is getting smaller.
-Ionic size : i) cationic radius < atomic size
ii) anionic radius > atomic size
iii) cation ( isoelectronic ), cation with higher  ionic charge <
iv) anions (isoelectronic ), anion with higher ionic charge >

b. Ionization Energy ( IE )
- Factors affecting the IE: nuclear charge, shielding effect, atomic size
- When going down the group, IE decreases.
- When across the period, IE increases
- First IE < Second IE < Third IE

c. Electronegativity
- When going down the group, the electronegativity of atom decreases
- When across the period, the electronegativity of atom increases
- F has the highest electronegativity.

d. Electron affinity
- A measure of how much an atom "wants" an electron
- Halogens have the greatest affinities

e. Metallic-nonmetallic Trend
- When across the period, the metallic properties changes form metal to metalloid and non-metal

f. Oxidation State
- Refer to the number of the Group in the Periodic Table
- When cations formed from the same element, cation with higher ionic charge are more stable

3.  Diagonal Relationship
- the atomic size, electronegativity, properties of compounds are similar

Thank you Dr.

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Hi Dr Sheela, nama saya Iman Adlina Binti Samsudin (A21HP0038) dan saya berasal daripada Batu Pahat, Johor.

Saya ingin bertanya tentang electron affinity.

1)      Adakah electron affinity untuk noble gasnya kosong sebab noble gas tu dah stabil or dengan kata lain takde energy yang akan direleased sebab takde terima electron

2)      Boleh ke assume electron affinity tu propotional dengan number of group but inversely proportional to electron needed to become octet/duplet

( cth: electron affinity highest utk group17 sebab cuma satu electron je yang diperlukan untuk buatkan atom tu stabil.)

Itu saja dari saya. Terima kasih Dr <3

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MUHAMMAD AMIRUL BIN KHAIRUL NIZAM (A21HP0080) FROM PASIR GUDANG JOHOR

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MUHAMMAD AMIRUL BIN KHAIRUL NIZAM (A21HP0080) FROM PASIR GUDANG JOHOR

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Hi dr , the summary that i can make from the first topic is , in the first topic

1- i know about the type / classification of elements (metal , metalloid , non-metal) which has different characteristic
2- i also understand what is electronic configuration that follow 2 principle and 1 rule  ( Aufbau principle , Hund's rule , Pauli' s Exclusion principle)
3-i also learn about the 6 trends that effected the occurs in the periodic table

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Hye Dr Sheela, my name is Irene Michelle Anak Dony (A21HP0040) from Kuching, Sarawak.

The summary from the previous topic that I've learned (Week 1) :
1. Atomic size : Across a period left to right, atomic radius decrease. Down a group top to bottom atomic radius increase.
2. Ionization energy (IE) : IE decreases down the group and inreases across a period (Exceptions at full and half full orbitals) . 2nd IE and 3rd IE always higher than 1st IE.
3. Electronegativity : Electronegativity is the tendency of a bonded atom to attract the shared electrons toward itself in a chemical bond. F has the highest electronegativity.
4. Electron affinity : Energy required or released when an electron is added into an atom in gas. More affinity, greater attraction.
5. Metallic - nonmetallic Trend : Across a period metallic character decreases. Down a group metallic character increases.
6. Oxidation States : Refer to the number of the Group in the Periodic Table.

Thank You Dr. :)

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Hello Dr Sheela. I’m Che Nurul Alya Fatnin binti Che Suhaimi (A21HP0024) and I’m from Pasir Gudang, Johor. Nice to meet you, Dr.

Firstly, from the previous class, I learned about organization of periodic table. In this topic, I’ve learned that periodic table has its trends that can be classification by parts which atomic size, ionization energy (IE), electronegativity, electron affinity, metallic non-metallic and oxidation states. Next, there were also about energy level, charge on nucleus and shielding effect that influence the trend properties in periodic table. After that, I also can recall back about how to write the proper electronic configuration since I almost forgot my past learning. Overall, based on my opinion, I loved to learn with Dr because its easy to understand. Thank you Dr Sheela.

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Hi Dr Sheela, my name is Miza Faiqah Binti Suhaimi (A21HP0059) and i'm from batu pahat, johor. From this topic which is topic 1, i had learned about the organization of atom in the periodic table, electronic configuration follow by 3 principles which is Aufbau Principle, Hund's Rule and Pauli's Exclusion Principle , also i learned about the trends in periodic table which contains 6 trends and each trends are important to understand. At first, it is quite difficult to understand but after revise back the topic i can understand now but need to always study because there is so much information to remember. But surely, must always referring on periodic table when study and also know how to do electronic configuration. Thank you Dr Sheela <3

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Hello Dr Sheela. Nice to meet you:). My name is Darshiny Muralitharan (A21HP0025). I'm from Negeri Sembilan.

From this topic, I've learned about electronic configuration which follows 3 rules which are Aufbau Principle, Hund's Rule and Pauli's Exclusion Principle. After that, I learned about  the main 6 trends, which are atomic size, ionization energy, electronegativity, electron affinity, metallic-nonmetallic trend and oxidation state. But I have to revise back this topic so that I could get a better understanding.

Thank you Dr:)

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hai dr sheela. nama saya nur suhaila binti shukor ( A21HP0151) dan berasal dari muar johor.

Boleh dr terangkan semula about oxidation state dengan lebih jelas ataupun yang mudah faham. sebab bila saya baca balik, jadi tak faham. a bit confusing dr . thank you dr <3

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Hello Dr. Sheela. I am Ain Asreena Binti Ramli (A21HP0008) from Gelang Patah, Johor Bahru.
From the previous class, I learned that periodic table has several trends. Firstly, atomic size decreases across a period and increases down a group. Next, for ionization energy,it increases across a period and decreases down a group. After that, electronegativity increases across a period and decreases down a group. The element gained highest electronegativity when it closed to fluorine. Other than that, I learned electron affinity. It means that the amount of energy released when an electron is added to an atom. It is the tendency of an atom to accept an electron to form an anion.
In addition, we have metallic and non metallic trend. Metal will form basic oxide and non-metallic will form acidic oxide.
But still, I have to revise these topic to make sure my knowledge about this topic is not misunderstood. I'm excited to learn this topic especially Dr Sheela who teaches us and I hope I can easily understand and remember it until the last semester. Thank you Dr for everything ;)

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Hi Dr. Sheela, My name is Balqis Binti Mohd Azman (A21HP0022) and I'm from Kota Tinggi, Johor. First of all, I'm very happy to see you as my lecturer for this semester. I hope I can follow all your rules and be a good student.

I'm sorry, Dr, but I have one question that makes me confused about the differences between nuclear charge and effective nuclear charge. From what I got from Google, nuclear charge is the total charge of the nucleus, and effective nuclear charge is the net charge that an outer shell electron experiences in an atom. But I can not imagine how it works.

Can you explain more about it. Thank you Dr.🌸

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Good day Dr Sheela.

I am Han Shin Ni (A21HP0033) from Kulai, Johor.

SUMMARY:

#Atomic sizes
Size of atoms getting bigger when going down the group and getting smaller when across the period.

#Ionization energy

IE decrease when going down the group and increase when across the period.

3rd IE > 2nd IE > 1st IE

#Electronegativity

F has the highest electronegativity. The nearer to F, the higher the electronegativity.

Electronegativity of metal < non-metal

#Electron affinity

A measure of how much an atom “wants” an electron.

Halogens have the greatest affinities.

#Metallic-non metallic trend

Across the period, metallic properties changes from metal → metalloid → non-metal

#Oxidation states

*refer to number of group in Periodic table*

#Diagonal relationship

Diagonal members have similar properties.

Thank you Dr.

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Hi, good afternoon Dr Sheela and everyone.  I'm Tan Sok Jing (A21HP0225) from Kluang, Johor.

Dr, do all the metal can form basic oxide or there are irregularities, because I saw some metal like lead and tin form amphoteric oxide when searching from internet. How do we identify that the which type of element will form amphoteric oxide ?Is all metalloid forms amphoteric oxide?

a) Beryllium Oxide
b)Tin oxide
c) PbO2
d) P2O3
e) Sb4O6

Dr, are the oxide a) to e) amphoteric oxide or form other oxide ? Thank you dr.

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Hi Dr Sheela..
My name is Muhammad Sabri Bin Zahari (A21HP0098). I'm from Tumpat, Kelantan
For the first chapter, i can summary that this chapter will be the main point for the further topics in this course. There are some terms that I should known well to understand about the six trends in periodic table such as electronic configuration, valence electron, energy level, shielding effects and nuclear charge. By understand that's term it will easily to understand about the six trends in periodic table. Then, I should follow the rules for the electronic configuration which is aufbau,hund's and Pauli exclusion principal. I hope that I can absorb as many as i can from your lecture in this course and able to practice in daily life. Thank you Dr...

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Hii dr sheela. i'm nurmaizurah binti nazri (A21HP0167) from Kulai Johor. Saya nak tanya utk confirmation sahaja betul ke the sentence about when metals let electrons go easily, it means i can say more willing to share. Is these two sentences have same meaning dr? and the rest I still need to revise again as a lot of facts of trends i need to comprehend back. Thankyouu Dr sheela

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Hi Dr Sheela and everyone. My name is Yasmin Binti Azman (A21HP0214) and I’m from Butterworth, Pulau Pinang. First of all, I must say that I’m very excited to learn more about this course as this is one of my favourite topics from Chemistry. Also, I’m very honored to have such an amazing and talented lecturer as you to be my coordinator for this semester. About this topic, I’ve learned that there are a few new elements that have been inserted along with the existed elements in the latest version of Periodic Table of Elements, such as Nihonium (Nh) and Moscovium (Mc). Secondly, I can also recall about how to write a proper electronic configuration, the rules in writing the electronic notation and the properties of the elements across the groups and periods respectively. Last but not least, I really hope that I can grab as much knowledge as I can throughout this course and have fun with everyone. T-T.

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Hi, and a very good afternoon Dr Sheela, i am Siti Nurfarieshah binti Suboh (A21HP0199) from Batu Pahat, Johor. For this topic, I've learned how to do electronic configuration in correct way using Aufbau Principle, Hund's Rule, and Pauli’s Exclusion Principle. Before this, idk how to do it properly and correctly which is good and better now.
Then, i learned trends in the periodic table, atomic size,ionic size( cation anion),isoelectronic ions, ionization energy, electronegativity, electron affinity, metallic-nonmetallic and oxidation number. And for me, we should or must always refer to periodic table as the table can be used to predict the properties of elements. and knowing the correct way to do electronic configuration is important as they helps classify elements into different blocks(spdf blocks), and surely i need to revise and re-study it back because a lot of content and weighty hehe. thankyou dr :)

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Hi Dr Sheela my name is Muhammad Afkar Bin Noralimin (A21HP0074) from Kemaman,Terengganu
From this topic, I had learned about electronic configuration, trends that happened in periodic table. There were 6 trends and it have relationship that affected each other (diagonal relationship). There were also about shielding effect and nuclear charge that the factors could affect the trends in periodic table. So far for this topic i need to revise it back because it have too much info hehe. thanks dr

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Hi Dr. Sheela. My name is Muhammad Hifzhuddin bin Yusri (A21HP0091) and I'm from Pekan, Pahang. Some of the things that I can briefly summarize from this topic is about the electronic configuration. It follows the three principles that are Aufbau, Pauli and Hund's principles. I also learn that there exist 6 trends in the periodic table. This topic really pique my interest and I will try to understand more about it.

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MUHAMMAD AFIQ BIN KHAIRUL ANUAR (A21HP0072) from Pasir Gudang , Johor

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I love to learned about first ionization energy , i easy to understand when i read the graph that Dr . Sheela shown. tq

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Hai Dr. Sheela. Nama saya Uzair Latif Hadi bin Abdul Rahman (A21HP0207). Berasal dari Semenyih Selangor. Saya pelepasan Matrikulasi Negeri Sembilan. Saya nak tanya kalau dekat ionization energy tuu,, kita mention pasal octet and duplet boleh kee??? Thank you dr...

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Hello Dr. Sheela. My name is Mohamad Faris Aiman (A21HP0063). I'm from Tapah Perak.
For topic 1, i learned that periodic table has itsy own trend and we can separate it into 6 parts which are atomic size, ionization energy, electronegativity, electron affinity, metallic-nonmetallic and oxidation number. Electron configuration is very important to determine each type of trends and also the shielding effect give some effect on those trends.