Atomic Structure & Periodic Table - P1T1

Alkali metals

The elements in Group 1 of the periodic table.

Atom

The smallest part of an element that can exist.

Atomic nucleus

Positively charged object composed of protons and neutrons at the centre of every atom with one or more electrons orbiting it.

Atomic number

The number of protons in the nucleus.

Chromatography

A separation technique used to separate a mixture of chemicals by distributing the components between two phases.

Compound

A substance made up of two or more types of atoms chemically combined together.

Crystallisation

A separation technique used to produce solid crystals from a solution by evaporating the solvent.

Displacement reaction

A chemical reaction in which a more reactive element displaces a less reactive element from its compound.

Electron

Negatively charged subatomic particle which orbit the nucleus at various energy levels. Very small relative mass (negligible).

Electron shell

Different energy levels in atoms occupied by electrons.

Element

A substance made up of only one type of atom.

Filtration

A separation technique used to separate solids from liquids.

Fractional distillation

A method of separating a mixture of substances according to their different boiling points.

Group (periodic table)

The columns of the periodic table represent different groups of elements. Elements with similar properties are in the same group.

Halogens

The elements in Group 7 of the periodic table.

Ion

An atom or molecule with an electric charge due to the loss or gain of electrons.

Isotope

Atoms of the same element with the same number of protons but a different number of neutrons.

Mass number

The total number of protons and neutrons in the nucleus.

Metals

Elements that react to form positive ions. Found to the left and towards the bottom of the periodic table.

Mixture

A mixture consists of two or more elements or compounds not chemically combined together.

Neutron

Neutral subatomic particle present in the nucleus of the atom. Relative mass of 1.

Noble gases

The elements in Group 0 of the periodic table.

Non-metals

Elements that react to form negative ions. Found towards the right and top of the periodic table.

Nuclear model

The nuclear atomic model stated that the mass was concentrated at the centre of the atom and that the nucleus was charged.

Periodic table

Table of elements arranged in order of atomic number and such that elements with similar properties are in the same column (group).

Plum pudding model

Atomic model devised after the discovery of the electron. The model suggests the atom is a ball of positive charge with negative electrons scattered through it.

Proton

Positively charged subatomic particle present in the nucleus of the atom. Relative mass of 1.

Relative atomic mass

An average value that takes account of the abundance of the isotopes of the element.

Simple distillation

A procedure by which two liquids with different boiling points can be separated.

Transition metals

The collection of metallic elements in the middle of the periodic table.