noun

the nucleus of a helium atom that is produced by some radioactive substances

noun

an ion with a negative electrical charge

noun

a type of particle in an atom that has the opposite electrical charge to the charge that a normal particle has, although they both have the same mass

noun

the smallest unit of any substance. It consists of a nucleus made of protons and neutrons with electrons travelling around it

adjective

relating to the atoms in a substance

noun

relative atomic mass

noun

the number of protons in the nucleus of an atom

noun

relative atomic mass

noun

an ion that has a positive electrical charge

noun

a part of a molecule consisting of a series of atoms connected in a line

noun

a part of an atom that moves around the nucleus (=centre) and has a negative electrical charge

noun

one of the parts that make up a subatomic particle such as a proton or neutron

adjective

a fissile atom or element can be separated into parts by nuclear fission

noun

a molecule that has an extra electron and can react very easily with other molecules. Free radicals sometimes form in the human body and can cause cancer.

noun

a material that consists of a layer of carbon that is only one atom thick

noun

an atom with an electrical force created by adding or removing an electron

adjective

relating to a mole (=a unit for measuring the number of molecules in a substance)

noun

a unit for measuring the number of molecules in a substance

adjective

relating to molecules

noun

the smallest part of an element or compound that is capable of independent existence. It consists of two or more atoms

noun

a simple molecule that can combine with other molecules to form a polymer

noun

a particle that is smaller than an atom and has no electrical charge

noun

the part of the nucleus of an atom that has no electrical charge

adjective

relating to the central part of an atom

noun

the central part of an atom, consisting of protons and neutrons

noun

the path that is taken by an electron around the nucleus of an atom

verb

to make a circular movement around the nucleus of an atom

noun

an extremely small piece of matter that is part of an atom, for example an electron, proton, or neutron

noun

a particle that is the same size as an electron but has a positive electrical charge

noun

the part of the nucleus of an atom that has a positive electrical charge

noun

a very small unit of matter that the particles of an atom consist of

noun

a group of atoms that are part of a molecule and do not change as a result of a chemical reaction

noun

the mass of an atom of a particular chemical element

noun

the valency of an atom

noun

a measurement of the ability of a chemical element to combine with other elements. The measurement is a number that shows how many atoms of the element combine with a single atom of the element hydrogen.