Question

The image shows the representation of an unknown element in the periodic table.

O
Symbol
Name
18.9984
Based on the representation which of the following statements about the element is true?
The combined number of protons plus electrons is 9.
The number of neutrons in an atom of the element is 10.
The combined mass of neutrons and electrons is 18.9984
The sum of the masses of protons and electrons is 18.9984

Answer 1

The number of neutrons in an atom is 10.

Step-by-step explanation:

neutron: mass # - proton

neutron: 19 (18.9984 (rounded)) - 9

neutron: 19-9 = 10

Answer 2

The number of neutrons in an atom of the element is 10.

Step-by-step explanation:

The number, 9 is the atomic number or proton number of the element. The number, 18.9984 is the atomic mass of the element. To calculate for atomic mass of an element one need to sum the number proton and number of neutron . The proton and neutron which are located in the nucleus of an atom contributes majorly to the mass of an atom. Mathematically,

Atomic mass = proton + neutron

Base on the picture above the atomic mass is 18. 9984 ≈ 19 and the proton or atomic number is 9 . Since the atomic mass and atomic number is known the numbers can be inserted in the formula

Atomic mass = proton + neutron

neutron = Atomic mass - proton

neutron = 19 - 9

neutron = 10

Therefore , the correct option is the number of neutrons in atom of the element is 10.