By number of protons/electrons.
Atoms of the same element can differ from one another in their atomic mass, which is determined by the number of neutrons in the nucleus. These variations are called isotopes. Isotopes of the same element have the same number of protons but different numbers of neutrons.
An element is a composition of many atoms. Thus you can hold NaCl (salt) in your hand. You can't hold the atoms it makes up.
No. Atoms of the same element have the same chemical properties.
Yes
number of protons
Neutrons. If the differ in electrons they are not neutral and if they differ in protons then they are no longer the same element as the number of protons determines the name of the element.
isotopes
Atoms of the same element are alike in terms of their number of protons, which determines the element. However, atoms of the same element can differ in the number of neutrons they contain, leading to different isotopes of that element.
During chemical reactions atoms remain unchanged.
In any element, all atoms are identical in terms of their number of protons in the nucleus, which determines the element's identity. However, atoms of the same element can differ in the number of neutrons, resulting in isotopes.
All atoms of the same element are not identical. The atoms of same element with different number of neutrons are called as isotopes. Although, the number of protons and electrons are same in every atom.
Atoms of the same element that differ in number of neutrons