A simple model of the atom, symbols, relative atomic mass, electronic charge and isotopes key terms

mass number

The total number of protons and neutrons in an atom. In Size and mass of atoms, this term helps explain calculate the number of protons, neutrons and electrons in an atom from atomic number and mass number for AQA GCSE Chemistry 8462.

atomic number

The number of protons in the nucleus of an atom, which determines the element. In Size and mass of atoms, this term helps explain calculate the number of protons, neutrons and electrons in an atom from atomic number and mass number for AQA GCSE Chemistry 8462.

protons

Positively charged subatomic particles found in the nucleus of an atom. In Size and mass of atoms, this term helps explain calculate the number of protons, neutrons and electrons in an ion from atomic number, mass number and charge for AQA GCSE Chemistry 8462.

mass number

The total number of protons and neutrons in an atom. In Size and mass of atoms, this term helps explain calculate the number of protons, neutrons and electrons in an ion from atomic number, mass number and charge for AQA GCSE Chemistry 8462.

SI units

Standardized units of measurement used to describe physical quantities, including atomic size.

nano prefix

A metric prefix indicating a factor of 10^-9, commonly used to express atomic dimensions.

atomic scale

The size of atoms compared to everyday objects, illustrating their minuscule dimensions.

physical world comparison

The method of relating atomic sizes to larger objects to understand their scale.

relative atomic mass

An average value that accounts for the abundance of different isotopes of an element.

isotope abundance

The relative amount of each isotope of an element present in a sample. In Relative atomic mass, this term helps explain define relative atomic mass as an average value that accounts for isotope abundance for AQA GCSE Chemistry 8462.

relative atomic mass

The weighted average mass of an atom of an element compared to 1/12th the mass of a carbon-12 atom.

isotope

Atoms of the same element with the same number of protons but different numbers of neutrons.

relative atomic mass

The weighted average mass of an atom of an element compared to 1/12th of the mass of a carbon-12 atom.

percentage abundance

The relative amount of each isotope of an element present in a sample, expressed as a percentage.

relative atomic mass

The weighted average mass of an element's isotopes compared to one twelfth of the mass of carbon-12.

isotope abundance

The relative amount of a particular isotope of an element compared to the total amount of all isotopes of that element.

energy level

A region around the nucleus of an atom where electrons are likely to be found, with lower energy levels being filled before higher ones.

innermost shell

The closest shell to the nucleus of an atom, which is filled with electrons before any electrons occupy higher energy levels.

electronic structure

The arrangement of electrons in an atom, represented by numbers indicating the number of electrons in each energy level.

sodium

A chemical element with the symbol Na and atomic number 11, represented in electronic structure as 2,8,1.

electronic structure

The arrangement of electrons in an atom, typically represented by numbers indicating the number of electrons in each energy level.

first 20 elements

The first 20 elements of the periodic table, which include hydrogen to calcium, used for representing electronic structures in diagrams.

electron-shell diagram

A visual representation showing the arrangement of electrons in an atom's energy levels.

first 20 elements

The first 20 elements of the periodic table, which include hydrogen to calcium, used for basic electronic structure interpretation.

outer-shell electrons

Electrons located in the outermost energy level of an atom, which determine its chemical properties.

electronic structure

The arrangement of electrons in an atom's energy levels or shells, which influences its reactivity and bonding.