Question

Atomic Structure 1: The Nucleus:

Question 1
An atom is shown by the symbol:

9943Tc

There are ________ neutrons in the nucleus of this atom.
Select one:

99

56

86

Answer 1

The atom with the symbol 9943Tc has 56 neutrons in its nucleus.

Step-by-step explanation:

An atom is shown by the symbol:
9943Tc

The atomic number of this atom is 43, which represents the number of protons in the nucleus. The mass number is 99, which represents the total number of nucleons (protons + neutrons) in the nucleus. To calculate the number of neutrons, subtract the atomic number from the mass number.

Number of neutrons = Mass number - Atomic number
= 99 - 43
= 56

Therefore, there are 56 neutrons in the nucleus of this atom.