Chapter 2 - Elements and the Periodic Table Flashcards
alkali metals
a group 1 metal; Li, Na, K, Rb, Cs, Fr
atom
basic building block of matter, which is made up of the subatomic particles protons, neutrons and electrons
atomic number
the number of protons in the nucleus of the atom; equal to the number of electrons
atomic radius
a measurement used for the size of atoms; the distance from the nucleus to outermost electrons
atomic theory of matter
all matter is made up of atoms; atoms are indivisible, atoms of the same element are identical and compounds are made up of different types of atoms in fixed ratios
block (periodic table)
one of four main parts of the periodic table where elements have the same highest energy subshell filled
Bohr model
a theory of the atom proposed by Niels Bohr which states that electrons in an atom occupy fixed, circular orbits that correspond to specific energy levels
chemical symbol
a symbolic representation of an element where the first letter is capitalised and the second letter is lowercase
compound
a pure substance made up of different types of atoms combined in a fixed ratio
condensed electronic configuration
a shortened way of writing electronic configuration by using the noble gas before the element
conflict element
elements mined in areas of war and conflict, which makes their use unsustainable
critical element
element heavily relied on by industry and society, which faces some form of supply uncertainty
effective nuclear charge
the net positive charge experienced by an electron in an outer shell of an atom; indicates the attractive force felt by the valence electrons towards the nucleus
electron
a negatively charged subatomic particle that occupies the region around the nucleus of the atom
electronic configuration
(in the shell model of an atom) a means of representing the number of electrons in each shell
electron shell
(in the shell model of an atom) the fixed energy level that corresponds to a circular orbit of the electrons
(in the Schrodinger model) a shell contains subshells and orbitals of equal or similar energy
electronegativity
the ability of an atom to attract electrons in a covalent bond towards itself
electrostatic attraction
the force of attraction between a positively charged particle and a negatively charged particle
element
a substance made up of atoms with the same atomic number
emission spectrum
a spectrum produced when an element is excited by heat or radiation; appears as distinct lines characteristic of the element
endangered element
element at risk of depletion on Earth, as natural deposits are used up
energy level
one of the different shells of an atom in which electrons can be found
excited state
describes an atom in which electrons occupy higher energy levels than the lowest possible energy levels
first ionisation energy
the energy required to remove one electron from an atom of an element in the gas phase
flame test
a test for the presence of certain metal ions or metals; when burnt in a flame, certain metals and metal ions produce a colour
ground state
a term used to describe an atom in which the electrons occupy the lowest possible energy levels
group (periodic table)
a vertical column of elements in the periodic table
halogen
a group 17 element; F, C, BR, I, At
ion
a positively or negatively charged atom or group of electrons
isotope
each of two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei
main group element
an element in groups 1,2 or 13-18 in the periodic table
mass number
the number of protons and neutrons in the nucleus of an atom
matter
anything that has mass and occupies space
metalloid
an element that displays both metallic and non-metallic properties; germanium, silicon, arsenic, tellurium
model
a description that scientists use to represent the important features of what they are trying to describe
neutron
an uncharged subatomic particle found in the nucleus of an atom
noble gas
an unreactive gaseous element in group 18 of the periodic table; with the exception of helium, noble gases have 8 electrons in their outer shells
nucleon
a particle that makes up the nucleus of an atom; protons and neutrons
nucleus
the positively charged core at the centre of an atom, consisting of protons and neutrons
nuclide notation
a way of representing an atom using the element symbol, atomic number (Z) and mass number (A)
orbital
a component of a subshell, a region of space in which electrons move and each holds two electrons (Schrodinger model)
period
a horizontal row of elements in the periodic table
periodic law
the way properties of elements vary periodically with their atomic number
periodic table
a table that organises the elements by grouping them according to their electron configurations
periodicity
the periodic pattern of properties of the elements
proton
a positively charged, subatomic particle bound to neutrons in the nucleus of an atom
quantised
in specific quantities or chunks
quantum mechanics
a branch of science that describes the behaviour of extremely small particles such as electrons
radioactive
spontaneously undergoing nuclear decay to produce radiation such as beta particles, alpha particles and gamma rays
Schrodinger model
a model for the behaviour of electrons in atoms that describes electrons as having wave-like properties
subatomic particle
a particle that makes up an atom - protons, neutrons and electrons
subshell
a component of a shell in the Schrodinger model, made up of orbitals; each subshell can be regarded as an energy level that electrons can occupy
transition metal
an element in groups 3-12 of the periodic table
valence electrons
an electron found in the valence shell; an outermost electron in an atom or ion
valence shell
the highest energy shell (outer shell) of an atom that contains electrons
