Solutions for Periodic Trends Guided Reading Exercises

Start by examining how atomic size changes as you move across a period or down a group. Atomic radius decreases from left to right across a period due to increased nuclear charge, which pulls electrons closer to the nucleus. Conversely, as you move down a group, atoms increase in size because of the addition of electron shells, which outweigh the increased nuclear charge.

Next, focus on ionization energy. This property refers to the energy required to remove an electron from an atom. It increases across a period as the atomic radius decreases, making it harder to remove electrons. Ionization energy decreases down a group because electrons are farther from the nucleus and are less tightly held.

Lastly, consider electronegativity, the tendency of an atom to attract electrons in a bond. Electronegativity increases across a period and decreases down a group. This pattern is essential for understanding how elements interact and form compounds in various chemical reactions.