Question

Choose the correct answer from the options given below.
An element with the atomic number 19 will most likely combine chemically with the element whose atomic number is

• A. (a) 17
• B. (b) 11
• C. (c)18
• D. (d) 20

Answer 1

The correct option is A

(a) 17

Part 1: Explanation for the Correct answer

Option (a) 17

1. Element with atomic number 17 is Chlorine.
2. Element with atomic number 19 is Potassium.
3. Potassium needs 1 electron less to become stable and Chlorine needs 1 electron to become stable.
4. As a result, Potassium and Chlorine will form an ionic bond and hence will form a compound $\mathrm{KCl}$.

Part 2: Explanation for the incorrect answer

Option (b) 11

1. Element with atomic number 11 is Sodium(Na)
2. It is also a metal like Potassium hence they both cannot chemically combine and form a compound.

Option (c) 18

1. Element with atomic number 18 is Argon.
2. It is a noble gas and we know that noble gases are non-reactive in nature due to their stability.
3. Hence they both cannot chemically combine and form a compound.

Option (d) 20

1. Element with atomic number 20 is Calcium(Ca)
2. It is also a metal like Potassium hence they both cannot chemically combine and form a compound.

Hence, an element with the atomic number 19 will most likely combine chemically with the element whose atomic number is option (a) 17