All atoms of the same element must have the same number of? protons. neutrons. compounds. electrons.

The correct answer is protons.

Explanation:

An ion is formed when an atom looses or gains electron.

Atomic number is defined as the number of protons that are present in an atom.  It is represented by the symbol 'Z'.

Atomic number = number of protons

Mass number is defined as the sum of number of protons and neutrons that are present in an atom.  It is represented by the symbol 'A'.

Mass number = Number of protons + Number of neutron

Each and every element has a unique number known as atomic number and atomic number is number is identified by the number of protons that are present in an atom.

All atoms of the same element has same number of protons. For Example: All atoms of sodium will have 11 number of protons.

Hence, the correct answer is protons.

protons

Explanation:

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