Question

9. The number of electrons in ⁴⁰k19 is (A) 19 (B) 18 (C) 20 (D) 40​

Answer 1

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• (A) 19

How to determine :

• The number of protons in the nucleus of the atom is equal to the atomic number (Z).

• The number of electrons in a neutral atom is equal to the number of protons.

• The mass number of the atom (M) is equal to the sum of the number of protons and neutrons in the nucleus.

• The number of neutrons is equal to the difference between the mass number of the atom (M) and the atomic number (Z).

Answer 2

Answer:

(C) 20

Hope its useful to u :-)