Question

osmium appears in the periodic table.

Rounded to the nearest whole number, how many neutrons, on average, are in an atom of osmium?

76
114
190
266

Answer 1

Answer: The correct answer is 114.

Explanation:

Atomic number is defined as the number of protons or number of electrons present in an element.

Atomic number = Number of protons = Number of electrons      ......(1)

Atomic mass is defined as the sum of number of protons and neutrons that are present in an element.

Atomic mass = Number of protons + Number of neutrons     .....(2)

For Osmium element:

Atomic number = 76

Atomic mass = $190.23\approx 190$

To calculate the number of neutrons, we use equation 2, we get:

Number of neutrons = 190 - 76 = 114

Hence, the correct answer is 114.

Answer 2

Answer: The number of neutrons in osmium metal are 114

Explanation:

Atomic number is defined as the number of protons or electrons that are present in a neutral atom.

Atomic number = number of protons = number of electrons

Mass number is defined as the sum of number of protons and neutrons that are present in an atom.

Mass number = Number of protons + Number of neutrons

We are given:

Osmium is 76th element of the periodic table.

We know that:

Atomic number = 76 = Number of protons

Mass number = 190

Number of neutrons = Mass number - Atomic number = 190 - 76 = 114

Hence, the number of neutrons in osmium metal are 114