grade 11 chem recap

atomic number

the number of protons in an atoms nucleus

mass number

the total number of protons and neutrons in the nucleus of an atom

isotope

atoms of the same element that have different numbers of neutrons

orbital

spaces around the atom that have a high probability of finding an electron

atomic size (radius)

the distance from the nucleus to the valence electron(s)

first ionization energy

the energy required to remove an electron from an atom

valence electron

the electrons that occupy the outermost energy level of an atom

stable octet

an arrangement of eight electrons in the valence shell of an atom

electron affinity

a measure of the change in energy that occurs when an electron is added to the outer energy level of an atom to form a negative ion

electronegativity

a relative measure of an atom’s ability to attract shared electrons in a chemical bond

isoelectronic

having the same electron configuration as another element, usually a noble gas

ionic bond

a bond between oppositely charged ions that arises from electron transfer (usually involves a metal and a non-metal)

covalent bond

a chemical bond in which two electrons are shared by two atoms

pure covalent bond

a chemical bond between two atoms with identical or nearly identical electronegativities

polar covalent bond

a covalent bond between two atoms in which the electron pair is unevenly shared

metallic bond

the force that holds metal atoms together

Dalton

atoms are solid spheres like billiard balls; did not address how things acquire electrical charge

Thomson

discovered the electron (proves atoms are divisible); atom is a sphere of uniform positive charge with electrons embedded in it (plum pudding model); no positively charged particles, no nucleus, electrons are stationary

Rutherford

atom has a very small, heavy nucleus (protons) surrounded by electrons; most of the atom is empty space; no energy levels for electrons; couldn’t account for the stability of matter

Bohr

same as Rutherford, but electrons are found in fixed energy levels around the nucleus; said electrons orbited the nucleus like planets orbit the sun (wrong)

Chadwick

discovered the neutron

Quantum Mechanical Model of the Atom (Schrodinger)

electrons are found in spaces around the nucleus called orbitals (s,p,d,f) which are defined by shape; orbitals still have corresponding energy levels; each orbital can hold 2 electrons; cannot determine exact location of an electron

average atomic mass

the average of the masses of all the isotopes of an element; given in atomic mass units (u)

isotopic abundance

the relative amount of an isotope of an element (expressed as a percent or decimal)

the mole

contains the same number of particles as exactly 12g of carbon-12

molecular mass

the mass of 1 molecule of a substance; given in atomic mass units

molar mass

the mass of 1 mol of a substance, numerically equal to the element’s average atomic mass (in g/mol)

empirical formula

the lowest whole number ration of atoms of each element in a compound

molecular formula

the actual number of atoms of each element in a molecule or formula unit

theoretical yield

the calculated amount of product that is produced by a chemical reaction

actual yield

the measured quantity of product obtained in a chemical reaction

solute

a substance that is dissolved in a solution

solvent

a substance that has other substances dissolved in it

solution

a homogeneous mixture of a solvent and one or more solutes

aqueous

a solution in which water is the solvent

electrolyte

a solute that conduct a current in an aqueous solution

non-electrolyte

a solute that doesn’t conduct current in an aqueous solution

dilute solution

a solution with a low molar concentration

concentrated solution

a solution with a high molar concentration

saturated solution

a solution in which no more of a particular solute can be dissolved at a specific temperature

molarity

the number of moles of solute present in one litre of solution

strong acid

an acid that completely dissociates into ions in aqueous solutions

weak acid

an acid that only slightly dissociates into ions in aqueous solutions