Chapter 2 - Atoms: Structure and Mass Flashcards
Alpha Particle
A positively charged particle formed from ionising radiation.
Atom
The basic building block of matter. It is made up of subatomic particles—protons, neutrons and electrons
Atomic Number
The number of protons in the nucleus of an atom; identical to the charge number of the nucleus; symbol Z.
Atomic Theory of Matter
All matter is made up of atoms. Atoms are indivisible, atoms of the same element are identical and compounds are made up of different types of atoms in fixed ratios.
Chemical Symbol
A symbolic representation of an element, usually one or two letters, where the first letter is capitalised and the second letter
is lower case.
Electron
A negatively charged, subatomic particle that occupies the region around the nucleus of an atom.
Electrostatic Attraction
The force of attraction between a positively charged particle and a negatively charged particle.
Mass Number
The number of protons and neutrons in the nucleus of an atom.
Isotope
Each of two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei.
Mass Spectrometer
An instrument that measures the mass-to-charge ratio of particles.
Matter
Anything that has a mass and occupies space
Mass Spectrum
A plot of the isotopic mass, relative to the mass of carbon-12 taken as 12 units exactly, against the relative abundance of each isotope present in a sample.
Model
A description that scientists use to represent the important features of a system or phenomenon
Neutron
An uncharged subatomic particle found in the nucleus of an atom
Nucleon
A particle that makes up the nucleus of an atom.
Nucleus
The positively charged core at the centre of an atom, consisting of protons and neutrons.
Periodic Table
A table that organises the elements by grouping them according to their electronic configurations.
Proton
A positively charged, subatomic particle bound to neutrons in the nucleus of an atom.
Radioactive
Spontaneously undergoing nuclear decay to produce radiation such as beta particles, alpha particles and gamma rays.
Relative Atomic Mass
The weighted average of the relative isotopic masses of an element on the scale where 12C is taken as 12 units exactly
Relative Isotopic Abundance
The percentage abundance of a particular isotope in a sample of an element
Relative Isotopic Mass
The mass of an atom of the isotope relative to the mass of an atom of 12C taken as 12 units exactly
Scanning Tunnelling Microscope (STM)
A microscope that images atoms by using a sharp metallic tip to sense the atoms on the surface of a crystal.
Standard Atomic Weight
The relative atomic mass of an element based on the agreed proportions of isotopes in a ‘normal’ sample of the element on Earth.
