AQA Atomic Structure Vocabulary

Vocabulary practice flashcards generated from the AQA Atomic Structure lecture transcript.

Proton

A subatomic particle located in the nucleus with a relative charge of $+1$ and a relative mass of $1$.

Neutron

A neutral subatomic particle located in the nucleus with a charge of $0$ and a relative mass of $1$.

Electron

A negatively charged subatomic particle orbiting the nucleus in shells, with a relative charge of $-1$ and a relative mass of $\frac{1}{2000}$.

Mass Number

The top number associated with an element symbol that tells the total number of protons and neutrons in the nucleus.

Atomic Number

Also called the proton number, it is the bottom number on an element symbol that indicates the number of protons.

Ion

A charged particle formed when an atom loses or gains electrons, resulting in an unequal number of protons and electrons.

Isotopes

Atoms of the same element with the same number of protons but a different number of neutrons, giving them different masses.

Plum Pudding Model

A model of the atom proposed by J.J. Thompson proposing a sphere of positive charge containing scattered negative electrons.

Gold Leaf Experiment

An experiment by Ernest Rutherford firing alpha particles at thin gold leaf, showing that most passed through empty space while a few deflected off a tiny positive nucleus.

Electrospray Ionization

A method in mass spectrometry where a sample is sprayed through a high-pressure jet under high voltage to produce gaseous positively charged ions through the loss of an electron.

Relative Atomic Mass

The average mass of an atom of an element measured on a scale in which the mass of an atom of carbon-$12$ is exactly $12$.

Relative Molecular Mass

The average mass of a molecule measured on a scale in which the mass of an atom of carbon-$12$ is exactly $12$.

Relative Isotopic Mass

The mass of an atom of an isotope of an element measured on a scale in which the mass of an atom of carbon-$12$ is exactly $12$.

Mass-to-Charge Ratio ($m/z$)

The mass of an isotope or fragment divided by its charge, plotted on the x-axis of a mass spectrum.

Molecular Ion Peak

The peak on a mass spectrum representing the whole unfragmented molecule that has been ionized, which is the last significant peak on the spectrum.

First Ionization Energy

The minimum amount of energy required to remove one mole of electrons from one mole of atoms in the gaseous state.

Shielding

The weakening of the attractive force between the positive nucleus and outer electrons due to inner electron shells.

Successive Ionization Energy

The energy required to sequentially remove more than one electron from the same atom.