Question

Does the nuclear charge increase as you go across periods (for atomic radii)?

Answer 1

Nuclear charge is basically the total charge of all the protons present in an atom. When we move across the group from left to right the atomic number of elements increases and thus the number of electrons and protons also increases. This will also affect the nuclear charge of the atom.

Complete answer:
Nuclear charge of the atom is the charge present on the nucleus of the atom. Since the nucleus of an atom consists of protons and neutrons. Neutrons have no charge and thus we can say that nuclear charge is the charge of all the protons present inside the nucleus of the atom. When we move across the period the atomic number of elements increases and thus the number of electrons and protons increase respectively. For a neutral atom the number of electrons and protons are equal. Therefore we can say that while moving from left to right across the period the number of protons increases, thus nuclear charge also increases. Since the positive charge increases, thus the attraction between the outermost electron and nucleus also increases. Thus the atomic radii decrease respectively.

Note:
It must be noted that while moving across the period the shell number of atoms remains same for all the elements in that period respectively. Thus more attraction increases while the number of shells is constant which makes the atomic radii of the atoms smaller while moving left to right in a period. Protons carry positive charge and electrons carry negative, hence there is force of attraction between them.