CHM 2045 Lecture Notes - Lecture 3: Formaldehyde, Barium Hydroxide, Molecular Mass

• School: University of Florida
• Department: Chemistry
• Course: CHM 2045
• Professor: Korolev Maria

Document Summary

Atom or atoms that have a net positive or negative charge: polyatomic ions-molecule with a charge. Cation-ion with positive charge: occurs when a neutral atom loses valence electrons, usually are metals. Anion- ion with negative charge: occur when a neutral atom gains electrons, usually nonmetals. Group 4- varies depending on atom, can be 4+ cation or 4- anion. Group 8- does not becomes ion because it has a full octet of valence electrons. Monoatomic ions- have only one atom: na+, cl-, ca2+, o2-, al3+, n3- Polyatomic ions- have more than one atom: oh-, cn-, nh4. Note: io(cid:374)s e(cid:374)di(cid:374)g i(cid:374)(cid:863)-ite(cid:863) usuall(cid:455) have less ato(cid:373)s tha(cid:374) io(cid:374)s e(cid:374)di(cid:374)g i(cid:374) (cid:862)-ate(cid:863: e. g. nitrate (no3) vs nitrite (no2) Covalent substances are molecules consisting of individual (usually nonmetal) molecules. Ionic substances are formula units of a continuous lattice of charged ions. Combination of cation and anion (cid:894)a(cid:374)io(cid:374) [(cid:374)o(cid:374)(cid:373)etal] gets the e(cid:374)di(cid:374)g (cid:862)-ide(cid:863)(cid:895)