Question

The weight of a single atom of oxygen is:
A) $1.057 \times {10^{ - 23}}g$
B) $3.556 \times {10^{ - 23}}g$
C) $2.656 \times {10^{ - 23}}g$
D) $4.538 \times {10^{ - 23}}g$

Answer 1

Hint: From the atomic weight (in grams per mole) of oxygen, obtain the weight of one mole of oxygen atoms. Divide this number with Avogadro’s number to obtain the weight of one oxygen atom.

Complete step-by-step answer:
We know that the mass of one mole of a substance is equal to that substance's molecular weight in gram. Atomic mass of oxygen is 16u.
Mass of 1 mole of Oxygen is Atomic mass= \[16g\]
We also know that a mole of a substance or a mole of particles is defined as exactly 6.022×1023 particles.
Now it became easier to calculate the weight of a single atom of oxygen is:
 Weight of single atom of oxygen
=\[\dfrac{{16}}{{6.022 \times {{10}^{23}}}}g\]
​=\[\]\[2.656 \times {10^{ - 23}}g\]

Oxygen is the 8th member of the periodic table with the symbol O and atomic number 8. Atomic mass of oxygen is 16u. Oxygen is a colorless and odorless molecule that is a gas at room temperature. Oxygen is a member of the halogen group in the periodic table.

Additional Information:
Let’s understand what exactly “mole” in chemistry is. The mole is the unit of measurement for the amount of substance in the International System of Units. The mole is a convenient unit to use because of the great number of atoms, molecules, or others in any substance. The mole can be defined as the number of atoms in \[12{\text{ }}grams\] of carbon-12.

Hence, Option (C) is the correct answer.

Note: In your calculation, do not enter molecular weight in place of atomic weight. Also write proper formulas. In other words, you have to divide atomic mass with Avogadro’s number. Do not divide Avogadro’s number with atomic mass or multiply atomic mass and Avogadro’s number.