Which statement concerning elements is true? (1) different elements must have different numbers of isotopes. (2) different elements must have different numbers of neutrons. (3) all atoms of a given element must have the same mass number. (4) all atoms ofa given element must have the same atomic number

The statement concerning chemical elements which is true is: (4) All atoms of a given element must have the same atomic number.

In Science, an atom can be defined as the smallest unit composed of matter that forms all chemical elements. Thus, atoms are fundamental building blocks of matter and determines (defines) the structure of all chemical elements.

Generally, atoms comprises three distinct particles and these are:

The number of protons found in the nucleus of an atom is referred to as atomic number and it is the same for all atoms of a specific chemical element.

In conclusion, all atoms of a particular chemical element must have the same number of protons or atomic number.

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the electronic configuration of an atom with eight electrons is 1s²2s²2p⁴. the orbital diagrams are shown in the figure.

as per the hunds rule:

1. electrons tend to avoid being in the same orbital as per as practicable.

2. electrons in different orbitals of the same energy will have their spin parallel.

this can be illustrated from the multiplicity of the orbitals of the atom. as there are four electrons in the p orbital and p orbital has 3 sub-shells. the electrons can be fed in different ways as shown in the figure but the correct orbital diagram will be as per the hunds rule.