Elements

Particle model of matter

- All matter consists of tiny particles called atoms that are too small to be seen and have mass.

- Atoms cannot be created or destroyed and are indivisible

- Particles are always moving. The hotter they are, the faster they move.

- All atoms of the same element are identical, but are different from atoms or other elements

- Atoms can join together to form larger particles called molecules

- Different atoms can combine to form compounds.

- Forces hold molecules and compounds together to stop separation.

Kinetic Theory of matter

The kinetic theory of matter states that all matter is composed of small particles which have space between them and are in random motion.

Elements

Elements are substances made up of only one type of atom, and are known as pure substances. Elements cannot be broken down into other substances as they are the simplest form.

Periodic Table

The periodic table groups together elements with similar properties. Horizontal rows in the table are called periods, and vertical columns are called groups. The main types of elements are metals, metalloids and non-metals. Elements are also classified on the basis of their chemical properties such as their atomic number, atomic mass, chemical symbol and name.

Chemical and Physical properties

Physical Properties-

- Liquid, solid or gas at room temperature

- Boiling and melting points

- Conducts electricity

- Density

- Strength

- Ability to be stretched into wires (ductility)

- Ability to be bent into shape (malleability)

- Appearance

Viscosity- Viscosity is the thickness of a liquid. Viscosity of an element is typically measured at 25 C due to the viscosity decreasing when heated. Chemically, the viscosity of a liquid is due to the size of particles and the attraction between particles.

Electrical conductivity- Conductivity is how easily something moves through substance. Electrical conductivity refers to how easily electricity flows through a substance.

Chemical Properties

Chemical properties of matter are only shown when two substances are reacted. It can be measured through- flammability, reactivity and toxicity.

Corrosion- Corrosion is a natural process in which a refined metal is converted to a more chemically stable form.

Subatomic particles and element properties- Atoms are made up of three main subatomic particles- elections, protons and neutrons. Protons and neutrons are found in the centre of an atom called the nucleus and electrons are particles that orbit the nucleus.

Metals- In a solid state the atoms of a metal are arranged in a 3D shape called a lattice. The positive nucleus and some electrons are attracted to each other, but the electrons are free roaming. Metal conducts electricity due to the electrons being able to flow through the solid , carrying electrical charge with them.

Non-metals- Electrons in non-metals are connected either to other atoms or to each other, which is the key difference to metals. This means that metals cannot conduct electricity as their electrons are used in connections rather than being free.

Most non- metals are glass at normal temperatures and some gasses such as helium are monatomic, meaning that each gas particle is a single atom. Some are diatomic, meaning that the atoms join together in pairs. Others are polyatomic meaning many of the atoms are joined together.