Unit 2 Vocabulary Flashcards
Dalton’s Atomic Theory
Elements = indivisible paricles called atoms;
Atoms of an element are identical (same mass) and atoms of different elements have different masses;
Compounds form when atoms of different element combine;
Atoms of element don’t change into different types of atoms in a chemical reaction
Mass number
The sum of the number of neutrons and protons in the nucleus
Changes to Daltons Atomic Theory
Isotopes- atoms of same element with different mass
Subatomic particles- atoms are divisible
Photon
Quantum of energy; each has specific wavelength frequency; given off as electrons bounce down energy levels; amount of energy depends on space between energy levels
Quantum
(Planck) Smallest amount of energy that can be gained or lost
Bright- Line Spectrum
Set of lines produced by an exited element (as electrons jump down energy levels, they most lose energy- in form of photon); each element has its own due to spacing between energy levels
Excited State
Some electrons are in higher than ground-state levels-
electrons jump up and gain energy/ fall down and give off energy (photon)
Ground State
All electrons are in their lowest possible energy levels
Bohr’s theory
Electrons must lose energy- atoms don’t obey laws of physics; as long as electrons are on their energy levels, they don’t lose energy; each energy level holds a certain number of electrons
Planck’s constant
Relates energy of a photon to its frequency
Thomson’s Atomic Model
(Plum Pudding Model) An atom is a ball of positive charge with electrons scattered through it
Thomson
Discovers electrons through Crook’s Tube experiment;
Also discovers neutrons
Rutherford’s Atomic Model
(Gold foil experiment) An atom is mostly empty space- it has a small, dense, positive nuclues surronded by orbiting electrons
Bohrs Atomic Model
An atom is mostly empty space- it has a small, dense, positive nuclues surronded by orbiting electrons on Definate Energy Levels!
Exothermic Reaction
Releases heat energy; energy leaves system; feels hot
Endothermic Reaction
Absorbs heat energy to power the change fo the reaction; feels cold
Activation Energy
Energy required to start a chemical reaction
Heisenberg Uncertainty Principle
It is impossible to know the location and velocity of an electron at the same time- you can only predict areas of finding and e-
PEL (n)
(Principal energy levels) n=1-7; made of 1 or more sublevels
Sublevels
of sublevels = PEL #
ex. PEL 3 has 3 sublevels;
Each sublevel is associated with a certain amount of energy; each sublevel is made up of 1 or more orbitals
s(2e) (1 orbital); p(6e) (3o); d(10e) (5o); f(14e) (7o)
Orbitals
Region of space occupied by no more than 2 electrons with opposite spins
Electron energy level breakdown
PEL(n) n =1-7
Sublevels=PEL number (ex. PEL 3 has 3 sublevels)
Orbitals=n squared
Electrons= 2n squared
How are two electron in different energy levels (or sublevels) different?
They have different amounts of energy
Only electrons in outermost PEL-determine activity of an element. Can be found by counting by roman numeral at top of periodic table.
Valence Electrons
Metric Breakdown
Kilo: 10 3 Centi: 10 -2 Milli: 10 -3 Micro: 10 -6 Nano: 10 -9
Ion
an atom or a group of atoms that has a positive or negative charge, must have outer energy level(shell) filled
a positively charged ion
cation
a negatively charged ion
anion
elements in groups 3-12, able to make various charges
Transitional Metals
elements in group 1(not hydrogen)
alkali metals
elements in group 2
alkaline earth metals
elements in group 17
halogens
elements in group 18
noble gases
2 of the same atoms in a molecule, 7 elements naturally occur: Br₂, I₂, N₂, Cl₂, H₂, O₂, F₂, acronym BrINClHOF
diatomic molecules
group
vertical column of elements, 18 groups
period
horizontal row of elements, 7 periods
have 1 electron in outer shell, have 1+ charge when forming ions
group 1 metals
have 2 electrons in outer shell, have 2+ charge when forming ions
group 2 metals
have 3 electrons in outer shell, have a 3+ charge when forming ions
group 13 metals
have 5 electrons in outer shell, have a 3- charge when forming ions
group 15 nonmetals
have 6 electrons in outer shell, have a 2- charge when forming ions
group 16 nonmetals
have 7 electrons in outer shell, have a 1- charge when forming ions
group 17 nonmetals
ionic compounds
must contain at least one cation and one anion, overall charge must equal zero, for writing identify cation and anion and charges they will form, determine number of cations and anions necessary for overall charge to equal zero(lowest common multiple), write symbol of cation↓ⁿ and symbol anion ↓ⁿ
naming cations
element name + ion,
ex. Na+ = sodium ion, magnesium ion = Mg²=
naming anions
changing ending of element name to -ide, then add ion,
ex. F- = fluoride ion, O²- = oxide ion, S²- = sulfide ion, P³- = phosphide ion, iodide ion = I-
equation for number of electrons held in each energy level
2(energy level #²)
have properties of both metals and nonmetals, found on the staircase
metalloids
