C2.2 - Bonding

• Shiny • Usually high MP and BP • Solid (apart from mercury) • Malleable • Ductile • Good conductors

• Dull • Usually low MP and BP • About half are solid and half are gas at room temperature • Brittle • Non-ductile • Poor conductors • Insulators

They can be separated by a zigzag boundary starting from under Boron.

A chemical property is a characteristic of a substance that can only be determined by studying its chemical reactions.

• Metals lose electrons to form positive ions, but non- metal atoms gain electrons to form negative ions. • Metal oxides produce alkaline solutions if dissolved in water. • Non-metal oxides produce acidic solutions if dissolved in water.

The electronic structure of an element shows how the electrons are arranged in atoms.

The outermost occupied shell in an atom is called the outer shell.

• The last number equals the non-IUPAC group number. • The number of numbers equals the period number. • The sum of the numbers equals the atomic number.

An ion is a charged particle formed when an atom, or group of atoms, loses or gains electrons.

• Metal atoms lose electrons to form positive ions. • Non-metal atoms gain electrons to form negative ions. • Non metals and metals gain or lose electrons to make a complete outer shell.

• An electron diagram represents the electronic structure of an atom or ion. • Circle to represent each shell. • Dots or crosses to represent its electrons - To also represent which electrons are gained. • Charge written outside the brackets on the top right. • Element symbol written in the centre

• When a metal reacts with a non-metal, electrons are transferred from the metal atoms to the non- metal atoms so that they both achieve more stable electronic structures. • Metal atoms become positively charged and non- metals atoms become negative ions.

• You can model the ions in the ionic compounds that is formed using a dot-and-cross diagram. • Electrons from one atom as dots. • Electrons from the other atom as crosses.

• Giant ionic lattice. • A structure of ionic compounds in which oppositely charged ions are held in a regular and repeating arrangement by strong electrostatic forces of attraction. • Ionic bonding - Strong electrostatic forces of attraction between oppositely charged ions.

• Ions are actually close together. • Bonds are forces rather than physical objects made from matter.

A covalent bond is a strong electrostatic force of attraction between the nuclei of two (bonded) atoms and their shared pair(s) of electrons.

• Using a dot-and-cross diagram. • Electrons from one of the bonded atoms are shown as dots. • Electrons from the other bonded atom are shows as crosses • Each pair of electrons in the shared area between the overlapping circles represent a covalent bond. • Only outer shells are usually shown.

A molecule that contains only a few non-metal atoms covalently bonded.

• Covalent bonds between the atoms in a simple molecule are strong. • Intermolecular forces between the molecules are weak.

Simple molecule have shapes, however a displayed formula does not show the three-dimensional shape of the molecule.

An arrangement of very many non-metal atoms joined by covalent bonds in a regular repeating arrangement.

• As having a giant covalent structure. • Each carbon atom is joined to four other carbon atoms by covalent bonds.

You use the empirical formula as there are many ions/very many atoms involved and it makes little sense to write a chemical formula with the huge numbers.

A substance with molecules made from many repeat units.