1: Atomic Structure and the Periodic Table Flashcards
Alkali metals:
The elements in Group 1 of the periodic table.
Atom:
The smallest part of an element that can exist. All substances are made up of atoms.
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:
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
