Question

this illustration shows the neutral atoms and ions for some of the elements in the periodic table. the period three elements illustrate how atomic and ionic radii change from left to right across the periodic table. the group 1a and group 6a elements illustrate how atomic and ionic radii change from top to bottom down the periodic table. what happens to the size of an atoms radius when it loses one or more electrons to become a positively charged ion? what happens to the size of an atoms radius when it gains one or more electrons to become a negatively charged ion? sodium (na) atoms form ions by losing one electron, while aluminum (al) atoms form ions by losing three electrons. how does losing more electrons affect the size of the ionic radius? phosphorus (p) atoms form ions by gaining three electrons, while chlorine (cl) atoms form ions by gaining one electron. how does gaining more electrons affect the size of the ionic radius? describe how ionic radius changes as you move from left to right across a period on the periodic table. describe how ionic radius changes as you from top to bottom down a group on the periodic table.

Explanation:

• When an atom loses electrons to become a positively - charged ion (cation), the number of electrons decreases while the nuclear charge (number of protons) remains the same. The remaining electrons are more strongly attracted to the nucleus, so the ionic radius decreases.
• When an atom gains electrons to become a negatively - charged ion (anion), the number of electrons increases. The electron - electron repulsion increases, and the effective nuclear charge (the net positive charge experienced by an electron) acting on each electron decreases. So the ionic radius increases.
• For cations (e.g., Na⁺ and Al³⁺), as more electrons are lost, the positive charge of the ion increases. The greater positive charge pulls the remaining electrons closer to the nucleus. So, losing more electrons (for cations) leads to a smaller ionic radius.
• For anions (e.g., P³⁻ and Cl⁻), as more electrons are gained, the electron - electron repulsion increases more significantly. The effective nuclear charge per electron is further reduced, so gaining more electrons (for anions) leads to a larger ionic radius.
• Across a period (left to right), for cations, the charge increases (e.g., Na⁺, Mg²⁺, Al³⁺). The ionic radius of cations decreases. For anions (e.g., N³⁻, O²⁻, F⁻), the charge is relatively more negative on the left. But when considering all ions in a period, first the cationic radii decrease (due to increasing charge and same electron shell for cations), then there is a jump (because from cations to anions, the electron shell changes in some cases), and then the anionic radii decrease (as the effective nuclear charge increases for anions across the period).
• Down a group, the number of electron shells increases. So, both atomic and ionic radii increase as there is more space for the electrons to occupy.

Answer:

• When an atom loses electrons to form a positive ion: The ionic radius decreases.
• When an atom gains electrons to form a negative ion: The ionic radius increases.
• Effect of losing more electrons (for cations like Na⁺ and Al³⁺): Losing more electrons leads to a smaller ionic radius.
• Effect of gaining more electrons (for anions like P³⁻ and Cl⁻): Gaining more electrons leads to a larger ionic radius.
• Ionic radius across a period: For cations, it decreases (e.g., Na⁺ > Mg²⁺> Al³⁺). For anions, it also decreases (e.g., N³⁻>O²⁻ > F⁻), but there is a discontinuity between the largest cation and the smallest anion in a period.
• Ionic radius down a group: The ionic radius increases.