Question

Two elements P and Q belong to the same period of the modern periodic table and are in group 1 and group 2, respectively. Compare the following characteristics in the tabular form.

1. Number of electrons in their atoms
2. Their tendency to lose electrons
3. Their metallic characters
4. Formation of their oxides
5. Formulae of their chlorides

Answer 1

As elements P and Q belong to the same period of the modern periodic table and are in group 1 and group 2, they belong to alkali metals and alkaline earth metals, respectively.

Characteristic	P	Q
(a) Number of electrons in their atoms	Valence electron = 1	Valence electrons = 2
(b) Their tendency to lose electrons	Can easily lose electrons	They will lose electrons easily but not as easily as alkali metals can.
(c) Their metallic characters	P is more metallic	Q is less metallic than P
(d) Formation of their oxides	React rapidly with oxygen in the air 4Na + O2 → 2Na2O	Less reactive than alkali metals
(e) Formulae of their chlorides	NaCl, KCl, CsCl	MgCl2, CaCl2, BaCl2