Write down the word that will correctly complete the following sentences:

(a) Relative atomic mass of a light element up to calcium is approximately …………… its atomic number.

(b) The horizontal rows in a periodic table are called ……………

(c) Going across a period left to right, atomic size ……………

(d) Moving left to right in the second period, number of valence electrons ……………

(e) Moving down in the second group, number of valence electrons ……………

Name or state the following with reference to the elements of the first three periods of the periodic table.

(a) Noble gas with duplet arrangement of electrons.

(b) Metalloid in Period 3.

(c) Valency of elements in Group 14 and 15.

(d) Noble gas having electronic configuration 2, 8, 8.

(e) Group whose elements have zero valency.

(f) A covalent compound formed by an element in period 2 and a halogen.

(g) Non-metallic element present in Period 3 of Groups 15 and 16.

(h) An electrovalent compound formed by an alkaline earth metal and a halogen.

(i) Bridge elements of Period 3 of Group 1, 2 and 3.

(j) Alkali metal in Period 3 that dissolves in water giving a strong alkali.

(k) Typical elements of Groups 14 and 15.

(l) Alkaline earth metal in Period 3.

(a) Name the method by which alkali metals can be extracted.

(b) What is the colour of the flame of sodium and potassium?

Arrange the following

(a) Elements of group 1, in increasing order of reactivity.

(b) Elements of group 17, in decreasing order of reactivity.

(c) He, Na, Mg (decreasing order of valency).

(d) Chlorine, sodium, magnesium (increasing reducing character).