Which of the following is true about an atom of iron and an atom of copper? 1 they have different masses. 2 both have the same properties. 3 they have an equal number of protons. 4 both have different types of sub-atomic particles.

Option (1) is the correct answer.

Explanation:

Both iron and copper atoms are transition elements. Atomic number of iron is 26 and atomic number of copper is 29.

As it is known that when atoms are neutral then number of protons and number of electrons are equal.

Hence, number of protons in iron and copper are different. Whereas atomic mass of iron is 55 g/mol and atomic mass of copper is 63 g/mol.

All the atoms consist of three sub-atomic particles that are protons, neutrons and electrons.

Thus, we can conclude that they have different masses, is true about an atom of iron and an atom of copper.