Question

You are provided with the table given below. Answer the questions that follow:

Hydrogen 1 H							Helium 2 He
Lithium 3 Li	Beryllium 4 Be	Boron 5 B	Carbon 6 C	Nitrogen 7 N	Oxygen 8 O	Florine 9 F	Neon 10 Ne
Sodium 11 Na	Magnesium 12 Mg	Aluminium 13 Al	Silicon 14 Si	Phosphorus 15 P	Sulphur 16 S	Chlorine 17 Cl	Argon 18 Ar
Potassium 19 K	Calcium 20 Ca

1. Which element has the largest size?
2. Name the most non metallic element.
3. Name the element with the lowest ionization potential.
4. Write the formula of the sulphate of the element with atomic no. 13.
5. What is the electronic configuration of the element in the fourth period that forms a dipositive ion?
6. Write the formula of the phosphate of the element in fourth period, second group.

Answer 1

1. Atomic size increases down a group (due to more shells) and decreases left to right across a period (due to higher nuclear charge). Potassium, being at the bottom-left, is the largest.
2. Fluorine (F)
3. Potassium (K)
4. Al₂(SO₄)₃.
5. The element in the fourth period that forms a dipositive ion M²⁺ must have 2 valence electrons. This element is calcium (Ca), located in Period 4, Group 2.
6. Ca₃(PO₄)₂