Periodic Table Detectives by Peh Kaijia

peh_kaijia2_1 — 2025-08-12 03:38:18 UTC

Select one element from your sheet that you can explain well.
Write a 3–4 sentence explanation of its properties, making sure to:
- Link to group and period position
- Use electronic configuration in your reasoning
- Refer to trends across periods or down groups

Mystery Element A1

2025-08-22 02:00:20 UTC

Element is Sodium from group 1, period 3.

Predicted Physical Properties: Soft, shiny, low melting point and good conductor of electricity, it has a low melting point as it has weak electrostatic forces.

Predicted chemical properties, it acts as a powerful reducing agent, and has 1 valence electron that is easily lost to achieve a stable electronic configuration thus it is reactive in water.

Compared to other elements in this group, Potassium is more reactive compared to sodium as it's single valence electron is further away from the nucleus compared sodium.

Element B1 (bromine)

davyn_yam_tian_xiang1_1 — 2025-08-22 02:06:57 UTC

Bromine is an element from group 17. Group 17 elements are halogens as they have a 1- electron charge in their atom and is prone to forming compounds by gaining one electron from being powerful oxidising agents. The group ranges from the highest reactivity to the lowest reactivity and lightest colour to darkest colour from top to bottom, Bromine is in the middle of group 17, period 3. Thus meaning that it is less reactive and darker than flourine and chlorine but more reactive and lighter than iodine and astatine. from this, we know bromine ions displaces iodine and astatine ions. group 17 melting and boiling point increases as it goes down the group, Bromine is a reddish-brown liquid in r.t.p.

Investigation on Element A2 (Potassium)

boo_jayden1_1 — 2025-08-22 02:07:52 UTC

Atomic mass of Potassium = 19

Electronic configuration: 2.8.8.1

Reactivity of potassium: most reactive in water

Explanation: The valence electrons in potassium is more ready to be lost as the valence electrons is the furthest from the nucleus amongst the three elements.

Melting Point of Potassium: lowest, 64 degrees Celcius

Boiling Point of Potassium: lowest. 760 degree Celcius

Explanation: Potassium has the weakest electrostatic forces of attraction between its positive nucleus and negative electrons, hence it requires less energy to overcome its weak electrostatic force of attraction.

Electrical conductivity of Potassium: lowest amongst the three

Explanation: Potassium has 4 electron shells, so the valence electron is more held in place, and is therefore not as mobile as the other elements in Group 1.

Element C3

2025-08-22 02:07:56 UTC

Element C3 is Neon, as it has the atomic number of 10. Since the atomic number is 10, it is found in group 18. Group 18 are noble gases.

Firstly, Neon is chemically inert, as it has filled valence electrons based on group 18 properties, thus they don't gain or lose electrons and are chemically unreactive.

Secondly, Neon has a low melting and boiling point, and it is insoluble in water. It also glows orange red in discharge tubes under room temperature. This is a distinct feature because this is not observed in other noble gases.

Thirdly, if we are to compare the reactivity series with other elements in group 18

We can conclude that Neon is less reactive than Helium but more reactive than Argon.

mystery element B2

leong_kai_en_kayden1_1 — 2025-08-22 02:09:51 UTC

predict that it has a high melting and high boiling point. and is black at room temperature (RTP). this is because colour intensity as it goes down the periodic groups because atoms get larger. and has low melting and boiling point as low energy is needed to overcome weak intermolecular forces as it has a simple molecular structure/.

predict, it has low recativity compared to bromine and chloride. and it undergoes displacement method. this is because more difficult for the positive neucleus to affect an electron into valence shell as the electrostatic forces of attraction are weak. a more reactive halogen will displacwe a less reactive halogen from it s aqueous halide solution.