unit 1 chemistry

add/subtract scientific notation

give both quantities the same exponent, add digits, and turn back into scientific notation

multiply/divide scientific notation

multiply/divide the first factors and add/subtract exponents

how many centigrams in 5 kilograms?

5kg/1 X 1g/1000kg (kg-g conversion) X 100cg/1g (g-cg conversion) = 0.5 cg. cross multiply and cancel out units

what 2 people suggested matter is made up of atoms

democritus and dalton

dalton’s atomic theory

atoms separate, combine, or rearrange in chemical reactions. atoms of different elements combine in whole-number ratios to form compounds. atoms could not be divided into smaller particles

atom

smallest particle of an element that retains the properties of that element

who proposed the nuclear atomic model

rutherford

who determined the mass-to-charge ratio of an electron

thomson

calculated the mass of an electron

millikan

plum pudding model

circle filled with randomly placed electrons and the empty space should have evenly distributed positive charges

nuclear atomic model

circle with a circle inside thats the nucleus. nucleus has protons and neutrons inside. electrons outside the nucleus

mass of neutrons vs protons vs electrons

neutrons and protons mass are relatively the same whereas electrons are a ton less

isotope symbolic notation

mass number over atomic number and then the symbol

how much is one atomic mass unit

1/12 the mass of a carbon-12 atom

the atomic mass of an atom accounts for — and —, making it usually —

the relative abundance, mass of each of the atom’s isotopes, not a whole number

how to calculate atomic mass of an element

add each isotope’s mass X percent abundance

electromagnetic radiation

type of energy that behaves like a wave. examples - light, x rays, radio waves, microwaves

amplitude

height of a wave from the origin to a crest or trough

frequency

number of waves that pass a given point in one second, measured in hertz (Hz)

quantum

minimum amount of energy that can be lost or gained by an atom

planck’s theory

for a given frequency, matter can emit or absorb energy only in whole number multiples of h times v

photoelectric effect

photoelectrons are emitted from a metal’s surface when light of a certain frequency shines on it

atomic emission spectrum

specific spectrum of colors due to frequencies of electromagnetic radiation emitted that are unique to each element

what’s happening when at atom is emitting light

photons having certain specific energies are being emitted

ground state

lowest allowable energy state of an atom

what did Bohr’s model of the atom predict

frequencies of the lines in hydrogen’s atomic emission spectrum

Bohr said the smaller an electron’s orbit, the — the atom’s energy level

lower

Bohr said the hydrogen atom emits a photon that corresponds to the difference between the — of its two orbits

energy levels

how did Bohr fail

he could only explain the atomic emission spectrum of hydrogen and not the other elements

what would have a larger wavelength - slow moving proton or fast moving golf ball? and why

slow moving proton because wavelength increases with decreasing mass and velocity

quantum mechanical model of the atom

modern atom model that treats electrons like waves

Heisenberg uncertainty principle

it’s impossible to know the velocity and position of a particle at the same time. cause if you mess with or touch it then it screws up ur calculations

Schrodinger wave equation

originally applied to the hydrogen atom, it led to the quantum mechanical model of the atom

atomic orbital

3 dimensional region around the nucleus representing the probability of finding an electron

electrons: Bohr model vs quantum mechanical model of the atom

QMM: treats electrons as waves and doesn’t describe their path around the nucleus. Bohr model: treats electrons as particles traveling in specific circular orbits

do atomic orbitals have an exactly defined size

no

what’s the max for how many electrons an orbital can have

2

how are s orbitals shaped

spherically

a principle energy has — energy sublevels

n

max number of electrons related to each principle energy level

2n squared

how many equal energy p orbitals

3

how to write name of isotope

element name dash mass number

Hydrogen-15

photon

particle of electromagnetic radiation with no mass that carries a quantum of energy

which color light produces a continuous spectrum

white

quantum number

the number assigned to each orbit of an electron

de broglie equation

all moving particles have wave characteristics and relates wavelength to frequency, mass, and plancks constant

principle energy level

major energy levels of an atom

energy sublevel

energy levels contained within a principle energy level

in Bohr’s model, for an electron to move farther away from the nucleus,… and when an electron moves closer to the nucleus…

it must absorb energy, it emits light as it releases energy so it is moving from excited to ground state

you got it

i believe in you

principle quantum number = Energy Level - “Shell” 

n² (last column) = Total number of orbitals present

sublevels; letters = Shapes of Probable Distribution of Electrons

number of orbitals related to sublevel = Maximum number of electron pairs within each sublevel

yes go