ch 1- atoms, elements and the periodic table Flashcards
atom
smallest unit of matter used in VCE chemistry
atomic number
number of protons in the nucleus of an atom
chemical symbol
abbreviation used to represent a chemical element
compound
two or more atoms of different elements bound together
electron
negatively charged particle that exists outside the nucleus of an atom
element
pure substance containing only a single type of atom
ion
atom that has lost or gained electrons to become a charged particle
isotope
variants of an element which have the same atomic number but a different number of neutrons in their nuclei
mass number
mass of an atom, equal to the sum of protons and neutrons
molecule
when two or more non-metal atoms bond by sharing electrons
neutron
neutral particle inside the nucleus of an atom
nucleus
region at the centre of an atom that contains protons and neutrons
periodic table
table of chemical elements in which elements are arranged in order of increasing atomic number
proton
positively charged particle inside the nucleus of an atom
subatomic particle
particle that exists inside the atom
Aufbau principle
rule that states subshells are filled by electrons from the lowest
to the highest energy level
blocks
assortment of elements into discrete categories based on which subshell their valence electrons are found in
electron configuration
arrangement of electrons in shells and/or subshells
energy shells/energy levels
orbits containing different levels of energy, around the nucleus of an atom where electrons are found according to the Bohr
and Schrodinger models
groups
columns in the periodic table
orbitals
regions with the highest probability of finding electrons
pauli exclusion principle
rule that states an orbital can’t hold more than 2 electrons
periods
rows in the periodic table
periodicity
characteristics of elements in a period
valence shell
outermost energy shell
valence electrons
electrons in the outermost shell of an atom
core charge
attractive force between the positive nucleus and valence electrons measured as the difference in the number of protons and inner electrons
electronegativity
how strongly an atom attracts electrons towards itself
first ionisation energy
energy required to remove the first valence electron from an atom
ion
atom that has lost or gained electrons to become a charged particle
metallic character
chemical properties associated with metals
metalloids
elements which possess properties that are in-between those of metals
and non-metals
noble gases
unreactive gases found in group 18 of the periodic table
octet rule
general principle which states that atoms like to have 8 electrons in their
valence shell for stability
reactivity
tendency of atoms to undergo a chemical reaction
critical elements
elements that are vital and considered in short supply unless they are recycled as sources could become depleted in 50–100 years
endangered
elements that have a limited supply left on Earth
lanthanoids
15 naturally occurring metallic chemical elements, whose atomic numbers fall between 57 (Lanthanum) and 71 (Lutetium)
recycled
converting a waste product into a reusable product
sustainable
can be produced at a rate that is greater than consumption without
compromising future generations
transition metals
elements that occupy groups 3 to 12 on the periodic table
acids
ionise in an aqueous solution to produce hydrogen ions
bases
produce hydroxide ions in solution
