Periodicity

• As atomic number increases, nuclear charge increases.
• Effective nuclear charge (Z eff) is the overall attractive force between negatively charged electrons and the positively charged nucleus.
• The number of electron shells affects the nuclear charge, with more shells dampening the charge and offering a shielding effect for outer electrons and generating a force of repulsion between adjacent shells.
• Atomic radius increases as the number of electron shells increases, with a larger atom being pulled closer to the nucleus and a smaller atom being pushed further away.
• The size of an anion is smaller than that of the atom, with more electrons dampening the nuclear charge and offering a shielding effect for outer electrons, generating a force of repulsion between adjacent shells.
• Ionization energy decreases as the number of electron shells increases, with a smaller atom being easier to remove an electron and requiring less energy.
• Electron affinity increases as the number of electron shells increases, with a smaller atom being more easily accepted an electron and releasing more energy.
• Electronegativity (EN) decreases as the number of electron shells increases, with the electron further away from the nucleus and harder to attract an electron.
• Non-metals gain electrons, with more electron shells dampening the nuclear charge and offering a shielding effect for outer electrons, generating a force of repulsion between adjacent shells.
• Metals lose electrons, with more electron shells dampening the nuclear charge and offering a shielding effect for outer electrons, generating a force of repulsion between adjacent shells.