Question

An atomic physicist determines that an atom is composed of 8 positively charged particles and has a mass of 15 amu. Which is the best conclusion that can be drawn? A. 7 neutrons and 8 protons. B. 7 electrons and 8 protons. C. 8 neutrons and 7 electrons. D. 8 electrons and 7 protons.

Answer 1

The answer is A

electrons essentially have no mass, so any answer involving electrons can be ignored.

Answer 2

Answer: The correct answer is Option A.

Step-by-step explanation:

There are 3 subatomic particles present in an atom. They are: protons, electrons and neutrons.

Protons carry positive charge, electrons carry negative charge and neutrons does not carry any charge.

Any neutral atom has equal number of protons and electrons.

Mass number is defined as the sum of number of neutrons and number of protons present in an atom. It is represented as A.

Mass number = Number of neutrons + Number of protons

We are given:

Number of positively charged particles = Number of protons = 8

Mass number = 15

Number of neutrons = 15 - 8 = 7

Hence, the correct answer is Option A.