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Describe an atom as an electrically neutral entity’s and the strcture of the atom

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Compare an atom to other items

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Compare an atom to a molecule

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Atoms are made of really small particles

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John dalton worked out so atomic weight and even created some symbols for atoms and molecules

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Parts of a atom

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John dalton developed a atomic theory in 1800s

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Atoms contained smaller pieces

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All matter is made of atoms

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Atoms are rearranged in a chemical reaction

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Electrons have negative charge

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All the atoms of a particular element are identical to one another

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Neil’s Bohr used an experimental evidence to support the idea that electrons occupy particular orbits as shells around the nucleus for the atom

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1. Used mathematical equations to describe the likelihood of finding an electron in a certain position.
2. Unlike the Bohr model, this model does not define the exact path of an electron but predicts the odds of the location of the electron. This model can be portrayed as a nucleus surrounded by an election cloud.
3. Where the cloud is most dense, the chance of finding the electron is greatest, and conversely, the electron is less likely to be in the less dense area of the cloud.

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1. Electron (-ve)
2. Proton (tve)
3. Neutron (no charge)

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Ernest Rutherford used experimental evidence to show that an atom must contain a central nucleus. This was a further evidence that an atom contained smaller pieces.

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Is Bohr’s model the existing model that we have now?

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What does Bohr’s model explain?

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What does Bohr’s model NOT explain?

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John Chadwick realised that most of the mass was doubled the number of protons

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John Chadwick discovered the neutron in 1932

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John Chadwick was a student of Rutherford

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Discovered the neutrons

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Electron (-ve)
Proton (+ve)
Neutron (no change)

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Schrodinger used mathematical equations to describe the likelihood of finding a electron in a certain position

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1. Used mathematical equations to describe the likelihood of finding an electron in a certain position.
2. Unlike the Bohr model, this model does not define the exact path of an electron but predicts the odds of the location of the electron. This model can be portrayed as a nucleus surrounded by an election cloud.
3. Where the cloud is most dense, the chance of finding the electron is greatest, and conversely, the electron is less likely to be in the less dense area of the cloud.

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Where the cloud is most dense the chance of finding an electron is greatest and conversely the electron is less likely to be found in a less dense area of the cloud

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Where the cloud is most dense the chance of finding an electron is greatest and conversely the electron is less likely to be found in a less dense area of the cloud

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How many neutrons or electrons there are in an atom

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How many neutrons or electrons there are in an atom

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Atoms cannot be broken down into anything simpler

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Compounds are formed when two or more atoms join together

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JJ Thomson discovered the electron in 1897

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Discovered the election in 1897

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Ernest Rutherford used experimental evidence to show that an atom must contain a central nucleus in 1911

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In 1911 he used experimental evidence to show that an atom must contain a central nucleus.

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Famous gold foil experiment

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Niels Bohr further developed Rutherford’s nuclear atom model in 1913

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SI units for mass is…
The mass of protons is…
The mass of neutron is…
The mass of electron is…

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He used experimental evidence to support the idea that electrons occupy particular orbits or shells around the nucleus of an atom

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John Chadwick realised that most of the mass was doubled the mass of protons and discovered the neutron in 1932

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How small, really, is a atom?

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Dalton-Atoms
Thomson-electrons
Rutherford-central nucleus/protons
Chadwick-neutrons in nucleus
Bohr-electron shells

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What each scientist found
Dalton-atoms
Thomson-electrons
Rutherford-central nucleus/protons
Chadwick-neutrons in nucleus
Bohr-electron shells

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Protons , neutrons, electrons

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Protons charge - +1
Neutrons charge - 0
Electrons charge- -1
Protons and neutrons mass - 1
Electrons mass 1/1840

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Number of protons = numbers of electrons

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Neutrons: Bottom number - top number
number of electrons= number of
protons

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The central nucleus consists of protons and neutrons and electrons surround it

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Electrons have negative charges and protons have positive charges

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Neutrons are supposed to keep the protons together

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2 protons
Proton+neutron=4
Number of neutrons= mass of neutrons-mass of protons
4-2=2

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Electrons’ mass is negligible because its mass is really really small so it doesn’t count

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Proton +neutron=4
No.of neutrons = mass no. _______
Proton number

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2 protons=Sub-atomic particles
2 electrons=Sub-atomic particles
2 neutrons=Sub-atomic particles

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Hydrogen has no neutrons
Has only one proton

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You can’t split a proton into half also neutrons

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Why is chlorine’s relative atomic mass 35.5?

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Every proton attracts an electron

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The two isotope chlorine atoms have the same number of protons but have a different number of neutrons

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Atoms of some elements
Same number of protons
Different number of neutrons

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Isotopes
1-atoms of the same element
2-same number of protons
3-different number of neutrons

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1)atoms of the same elements
2) the same no. Of protons
3) different No neutrons

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Cl 17 35
Proton- 17 Neutron- 18 Electron-17
Cl 17 37
Proton- 17 Neutron- 20 Electron-17

Proton(+1)  Neutron(0)  Electron(-1)

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Mass number minus proton number is the number of neutrons

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How many electrons are there for lithium??????????

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1st shell must have 2 elements max

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*1) First shell must have two electrons maximum
*2) second and third shell has a maximum of 8 electron
3) I - one outer atom
4) same row same colunm
*boss model up till only

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1.) 1st shell must have maximum 2 electrons
2.) 2nd and 3rd shell must have a maximum of 8 electrons
3.) I-1 outermost electron
4.) Same row, same number of occupied electron shells
*Bohr's model only from 1-20 atomic number

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Boron-10 has 5 neutrons
Boron-11 has 6 neutrons
Boron=10.8

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Protons=Top number(proton atomic number)
Neutrons= Bottom number - top number(relative atomic mass - proton atomic number)
Electrons= Protons

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Shellls

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Valence=outermost

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1st 2nd and 3rd conclusion

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Same row=same number of occupied electron shells

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Row=period

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Another word for row is period

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I-1 outermost electron
II-2 outermost electrons
*Represent number of electron in outermost shell
*Outermost=Valence
*Column=Group(Roman numerals,I,II,III,IV)

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Electrons must be spaced apart from each other and have to be in pairs

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Outermost- valence

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Rows = period

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1st shell—max 2 electrons
2nd 3rd shell—max 8 electrons
Columns—groups (Roman numerals,I,II,III,V,IV)
Rows—period(Arabic numbers,1,2,3,4

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The first period(row) consists of 2 elements -> Hydrogen and Helium

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There is the same number of protons as the number of electrons because all atoms are electrically neutral

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Noble gases are unreactive/inert because they have a stable electronic configuration with full electron shells

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Li- 2,1
Na- 2,8,1
K- 2,8,8,1
Be- 2,2
Mg- 2,8,2
Ca- 2,8,8,2
2.8.8.2

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If proton number exceeds 20, only need to draw outermost shell

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There are the same number of protons and electrons because it has to be electrically neutral

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But groups?

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What information does it tell us if the elements are in the same group?

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What information does it tell us if the elements are in the same group?

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All the elements in one group have the same or similar reactions