Answer:
True
Step-by-step explanation:
Given parameters:
Number of neutrons = 21
Mass number = 40
Unknown:
Number of electrons = 19
Number of neutrons = 21
Solution:
To find verify whether it is true or false, we must understand the relationship between the given species.
Protons are the positively charged particles
Neutrons do not carry any charge
electrons are the negatively charged particles
Mass number = number of protons + neutrons
Number of protons = 40 - 21 = 19
In an atom, the number of protons and electrons are the same for charge stability.
Number of electrons = 19