GCSE Chemistry: Atomic Structure and the Periodic Table

Flashcards covering key concepts from GCSE Chemistry on atomic structure and the periodic table.

Atom

The smallest particle of an element that retains its chemical properties.

Element

A substance made up of only one type of atom.

Compound

A substance made from two or more different types of atoms chemically bonded together.

Mixture

Two or more substances not chemically bonded, which can be separated by physical means.

Subatomic particles

Particles within an atom, including protons, neutrons, and electrons.

Atomic number

The number of protons in an atom.

Mass number

The total number of protons and neutrons in an atom.

Isotopes

Atoms of the same element with different numbers of neutrons.

Energy levels (shells)

Arrangement of electrons in an atom, typically 2, 8, 8 for the first three levels.

John Dalton's atomic theory

Atoms are solid spheres; different elements are made of different atoms.

J.J. Thomson's model

Plum pudding model; atoms are spheres of positive charge with electrons inside.

Rutherford's model

Atoms have a tiny positive nucleus; electrons orbit at a distance.

Alpha particle scattering experiment

Showed that most particles passed through, indicating atoms are mostly empty space; some deflected, showing a positive nucleus.

Niels Bohr's contribution

Electrons orbit the nucleus in fixed energy levels (shells).

James Chadwick's discovery

The neutron, which explains the difference in mass between isotopes.

Dmitri Mendeleev

Created the first periodic table, arranging elements by atomic mass and properties.

Properties of noble gases

Unreactive, full outer shell, low boiling points that increase down the group.

Group 1 metals properties

Very reactive, soft, low melting points, and form +1 ions.

Reactivity trend of Group 1 metals

Reactivity increases down the group as outer electron is further from the nucleus.

Halogens properties

Non-metals, form -1 ions, toxic, and have coloured vapours.

Reactivity trend in Group 7

Reactivity decreases down the group.

Displacement reaction in Group 7

A more reactive halogen displaces a less reactive one from a compound.

Properties of transition metals

Good conductors, high melting points, malleable, and form coloured compounds.

Difference between transition metals and Group 1 metals

Transition metals are less reactive, harder, have higher melting points, and can form ions with different charges.

Uses of transition metals

Used as catalysts and in construction due to strength and resistance to corrosion.