topic 1: key concepts in chemisty Flashcards
anion
a negatively charged ion, formed when an atom gains at least one electron
atom
the smallest part of an element that can exist. all substances are made up of atoms.
atomic nucleus
positively charged object composed of protons and neutrons at the centre of every atom with one or more electrons orbiting it
atomic number
the number of protons in the nucleus
avogrados constant
the number of atoms, molecules, or ions in a mole of a given substance s
cation
a positively charged ion. formed when an atom loses at least one electron
compound
a substance made up of two or more types of atoms chemically combined together
concentration
the amount of substance (eg. the mass) in a certain volume of solution
conductor
a material that contains charged particles which are free to move to carry electrical or thermal energy
conservation of mass
a law which states that no atoms are lost or made during a chemical reaction so the mass of the products equals the mass of the reactants
conductor
a material that contains charged particles which are free to move to carry electrical or thermal energy
covalent bonds
a shared pair of electrons between two non metals
dalton model
dalton described atoms as solid spheres, stating that different spheres made up the different elements
diamond
a giant covalent structure which is made up of carbon atoms each of which form four covalent bonds with four other carbon atoms
electron
negatively charged subatomic particle which orbit the nucleus at various energy levels. very small relative mass. (negligible).
electron shell
different energy levels in atoms occupied by electrons
electrostatic forces
the strong forces of attraction between oppositely charged ions
element
a substance made up of only one type of atom