1. Atomic Number: The atomic number of elements increases from left to right across the period. This means the number of protons in the nucleus increases from one element to the next.
2. Metallic Character: Metallic character decreases from left to right across the period. This means that elements on the left side of the period tend to be more reactive metals, while those on the right side are less reactive nonmetals.
3. Nonmetallic Character: Conversely, nonmetallic character increases from left to right across the period. Elements on the right side of the period are more likely to form covalent compounds, while those on the left tend to form ionic compounds.
4. Atomic Radius: The atomic radius generally decreases from left to right across the period. As the atomic number increases, more protons are added to the nucleus, which increases the positive charge and pulls the electrons closer to the nucleus, reducing the atomic radius.
5. Ionization Energy: Ionization energy generally increases from left to right across the period. It becomes increasingly difficult to remove an electron from an atom as the number of protons in the nucleus increases.
6. Electron Affinity: Electron affinity, the energy change that occurs when an atom accepts an electron, generally shows an irregular trend across a period.
7. Electronegativity: Electronegativity, the ability of an atom to attract electrons, generally increases from left to right across the period. This is due to the increased effective nuclear charge experienced by electrons as the atomic number increases.
