Chem I Notes

Periodic Table Summary

Alkali Metals

• One valence electron

• Highly reactive (react with halogens to form salts)

Alkaline Earth Metals

• Two valence electrons

• Highly reactive with unfilled outer shells

Transition Metals

• Varying properties

• Often have multiple valence electrons

Metalloids

• Conduct electricity moderately

• Possess characteristics between metals and nonmetals

Noble Gases

• Stable and non-reactive

• Full valence shells (e.g., neon, argon)

Group Facts

• Group 1 (Alkali Metals): Li, Na, K, Rb, Cs, Fr

• Group 2 (Alkaline Earth Metals): Be, Mg, Ca, Sr, Ba

• Group 3A: B, Al, Ga, In, Tl

• Group 4: C, Si, Ge, Sn, Pb

• Group 5A: N, P, As, Sb, Bi

• Group 6A: O, S, Se, Te, Po

• Group 7A: F, Cl, Br, I (highly reactive)

• Group 8A: Ne, Ar, Kr, Xe (highly stable)

Structure of the Atom

• Protons: Positively charged; identity of the atom

• Neutrons: Neutral; buffer in the nucleus

• Electrons: Much smaller; responsible for reactivity

Ions

• Cations: Positively charged ions (lost electron, typically metals)

• Anions: Negatively charged ions (gained electron, typically nonmetals)

Chemical Reactions

• Balancing Equations Example: C₃H₈ + 5O₂ → 3CO₂ + 4H₂O

• Diatomic Elements: H, I, Br, O, N, Cl, F

Octet Rule

• Atoms aim for 8 valence electrons to be stable (e.g., in H₂O)

Mixtures

• Homogeneous: Evenly mixed (solution)

• Heterogeneous: Distinguishable parts

Isotopes

• Atoms with the same protons but differing neutrons; chemically alike due to identical electron arrangements.