Ionic Bonding
Ionic Bonds
- Electrons are transferred from one atom to another creating ions
- Metal + nonmetal
○ Metals form cations (lose e- bcuz low IE) and nonmetals form anions (gain e- bcuz high IE)
○ Cations are attracted to anions; (+) & (-) attract
○ Nonmetal achieves electron configuration of next noble gas and valence orbitals of metal are emptied
- Ions are usually more stable than atoms but still unstable because are electrically charged
- Before losing/gaining electrons, atoms are neutral (no charge)
- All elements with more than one charge are metals and give away e- (+)
Types of Ions
- Ions: electrically charged particle
Monatomic = one type of atom (same element)
- H+, Ca2+, N3-
Polyatomic = many types of atoms (different elements) with a charge; small charged molecules
- Held by covalent bonds and net charge is not zero
Lewis Dot Structures
- Valence electrons represented by dots, no more than two per side
- Can show rearrangement of electrons during chemical reactions
- Note:
→ has lost an e- so C will have only 6 ve 
Binary Ionic Compounds
- Contains ions of only two elements Formula: cation first, then anion
- Charges of atoms written as superscript (on top)
○ Number of atoms written as subscripts (on bottom) 
○ Cation has positive charge while anion has negative
- The total (net) charge on the compound should be zero
Naming Types of Ionic Compounds
- If cation has more than one valence (can have different charges) indicate the charge using roman numerals in parentheses after the cation name
- FeO = iron (II) Oxide Binary Ionic Compounds
- Name cation using its element name
- Some have common names (ex. Water, sodium)
- Name anion by dropping ending of the element name and adding -ide
○ Ex: Calcium Phosphide → -ide shows that there is one anion
Polyatomic Ionic Compounds
● If anion is polyatomic, name it using the ions name
● Will be polyatomic if ends in -ate or -ite
- -ate = has more oxygen ions
- -ite = has less oxygen ions
● Treat as one whole unit
● Always use parenthesis () unless there is only one
● Fe(OH)₂
○ 3 ions
○ 5 atoms: two subscript belongs to hydrogen AND oxygen
Covalent Bonding
- Covalent Bonds: formed by a share of a pair of electrons between two atoms that completes the electron configuration of both atoms
○ Between nonmetals
- Shared electrons give a lower energy state because they are simultaneously attracted by two nuclei
Types of Covalent Bonds
- Polar covalent bonds = unequal sharing of e-; charges indicated using small delta
○ Due to electronegativity difference: electrons pulled to more electroneg. atom
■ More electroneg. atom becomes slightly (-) (higher e- density)
■ Less electroneg. atom becomes slightly (+)
○ Soluble in water (hydrophilic) cuz of charge
- Nonpolar covalent bonds = atoms of the same element or with similar electronegativity so have equal sharing of e-
○ Ex: O₂, N₂, Cl₂
○ Even though is bonded to itself, is more stable BUT is a strained bond so is ready to react with a better bond
○ No charge
Properties of Covalent Bonds
● Low melting points
○ Bcuz attraction between e- are easy to overcome
- Soft, flexible
- Many won’t dissolve/be disrupted in water (nonpolar)
○ Cannot conduct electricity even when dissolved bcuz no charges (+ or -) are present
○ Polar covalent can dissolve cuz of charges
- Many are liquids at room temperature
- Flow of electricity:
○ NO for nonpolar covalent bonds bcuz e- are tightly held & no charges are present
○ YES for polar covalent bonds in molten form bcuz of charges Naming Covalent Bonds
- Rule 1: Element with lower group number (more left) goes first
- Rule 2: If elements in same group then greater period number (more down) goes first
- Rule 3: 2nd element in compound ends in -ide
- Use greek prefixes to determine number of atoms
Mono: one Di: 2 Tri: 3 Tetra: 4 Penta: 5
Hexa: 6 Hepta: 7 Octo: 8 Nona: 9 Deca: 10
- If there is only one atom of first element, them NO prefix → just elemental name ○ Ex CO: Carbon monoxide
- NO CRISS CROSS METHOD