Which of the following is the pair of shortest and longest periods in the modern periodic table?

(a)

1^st, 2^nd

(b)

2^nd, 3^rd

(c)

5^th, 7^th

(d)

1^th, 6^th

Pick the correct order on decreasing trend of atomic size

(a)

Mg, Mg⁺, Mg²⁺

(b)

Mg⁺, Mg²⁺, Mg

(c)

Mg²⁺, Mg⁺, Mg

(d)

Mg²⁺, Mg, Mg⁺

Among the halogens which one is most electro-negative?

(a)

Iodine

(b)

Chlorine

(c)

Bromine

(d)

Fluorine

The acid which makes iron passive is _______________

(a)

Conc.HCl

(b)

Cone.H₂SO₄

(c)

Cone.HNO₃

(d)

Cone.HF

The green layer found on the copper vessel is due to the formation of ________

(a)

basic copper carbonate

(b)

cupric oxide

(c)

cuprous oxide

(d)

copper chloride