Chemical bonding + electronegativity

What is ionic bonding?

• a bond formed by electrostatic attraction between positive and negative ions (cations & anions)

How do ionic bonds work?

• One atom donates one or two electrons to another.

metal and non-metal

What is covalent bonding?

• has a pair of electrons with opposed spin shared between two atoms with each atom giving one electron.

How does covalent bonding work?

shared pair of electrons

(Non metal and nonmetal )

What is coordinate bonding?

• a covalent bond in which both electrons come from one of the same atoms

(one doesn’t share) must have a lone pair

What is a metallic bond?

sea of delocalised electrons given by each atom. electrostatic forces between positive ions and electron

What is a lone pair in a covalent bond?

pair of valence electrons (in outer shell) that are not involved in covalent bonding

In a covalent bond, electrons repel each other, Why?

• atoms get too close together

• inner electron and nuclei will repeal each other

• bond strength determined by this factor

What minimises electron repulsion?

• repulsion overcome by attraction between electrons and protons of both nuclei

• electrons also have opposing spins

How is the strength determined in a metallic bond?

• as strength of bond increases the number of delocalised electrons also increases

In an ionic bond, how is electron repulsion minimised?

• cations and anions are arranged so that each anion is surrounded by a certain number of cations - same with anion - maximum electrostatic attraction obtained.

What is electronegativity?

measure of electron- attracting power of an atom in a covalent bond.

Why does electronegativity increase across a period?

because more nuclear charge/ protons increases, pulling outer electrons closer while the atomic radius decreases.

Why does electronegativity decrease down a group?

• atoms gain extra electron shell, increasing distance and shielding - weaker attractive force.

What is a dipole/polar?

• imbalance in electron density

What is non-polar?

electronegativity always the same - no imbalance