Which of the following is the correct electronic configuration of potassium ?

1. 2, 8, 9
2. 8, 2, 9
3. 2, 8, 8, 1
4. 1, 2, 8, 8

The mass number of an atom whose unipositive ion has 10 electrons and 12 neutrons is :

1. 23
2. 22
3. 20
4. 21

The correct electronic configuration of Fluorine is:

1. 2, 8
2. 8, 2, 1
3. 7, 2
4. 2, 7

An element 'A' has 15 electrons and 16 neutrons. The correct representation of this element is:

1. ¹⁶₁₅A
2. ³¹₁₆A
3. ³¹₁₅A
4. ¹⁵₁₆A