atom structure Flashcards
What is an atom?
An atom is the smallest part of an element that can exist. They consist of electrons surrounding a nucleus that contain protons and neutrons.
What is a molecule?
A group of two or more atoms chemically joined together forming an identifiable unit which retains the properties and composition of the substance.
What is an atomic number?
The number of protons in the nucleus of an atom, which is characteristic of a chemical element and determines its place in the periodic table.
What is an mass number?
The total number of protons and neutrons in a nucleus.
What is a isotopes?
Atoms of the same element contain the same number of protons and electrons but a different number of neutrons. Therefore, they have the same atomic number but a different mass number.
What is relative atomic mass?
Weighted average mass of one atom of an element, taking into account the abundance of all the isotopes of that element. It is measured as a ratio 1/12 of the mass of an atom of carbon-12.
