Questions :

1. The number of electrons in Na⁺ (atomic number = 11) are
(a) 11
(b) 10
(c) 12
(d) 13

2. There are four elements P, Q, R and S having atomic numbers of 4, 18, 10 and 16 respectively. The element which can exhibit covalency as well as electrovalency will be:
(a) -P
(b) Q
(c) R
(d) S

3. The maximum number of electron in 3rd shell can be
(a) 8
(b) 18
(c) 32
(d) 50

4. The valency of Al with atomic number 13 is
(a) 3
(b) 2
(c) 4
(d) 1

5. Which of the following is used in radio carbon dating
(a) ¹²C₆
(b) ¹³C₆
(c) ¹⁴C₆
(d) ²³⁸C₉₂

6. The maximum number of electrons in last shell is equal to
(a) 8
(b) 18
(c) 2
(d) 1

7. The mass number of two atoms X and Y is the same (40 each) but their atomic numbers are different (being 20 and 18 respectively). X and Y are examples of :
(a) chemically similar atoms
(b) isotopes
(c) solid and liquid metals
(d) isobars

8. Name the element which has electronic configuration 2, 8, 8,1
(a) K
(b) Na
(c) Ca
(d) Ar

9. Anode rays are produced when
(a) cathode is perforated
(b) anode is perforated
(c) when low voltage is passed
(d) when pressure is high

10. The number of electrons in F-, if atomic number of F is 9 are
(a) 9
(b) 8
(c) 10
(d) 11