2. Atoms, Atomic Structure, and Moles

particle theory of matter was supported as early as…

400 BCE

what is the word atom based from?

Greek word for indivisibile

what parts make up the nucleus of atom?

protons and neutrons

beta particles are

negative

gamma particles are

neutral

alpha particles are

positive

____ force keeps the nuclei together

strong nuclear

in periodic table, the top number is

atomic number

in periodic table, the bottom number is

atomic mass

in hyphen notation, the number on the right is

atomic mass

what part of an atom determines its identity?

proton

in isotope notation, the top-left number is

atomic mass

in isotope notation, the bottom-left number is

atomic number

what are ions?

charged particles

cations are

positively charged particles

anions are

negatively charged particles

what does amu of an element represent?

grams/mol

what is the unit representation for the avagadro number?

particles/mol

what is the numeric representation for the avagadro number

6.022×10²³

1 amu is ____ (fraction) of a ____ atom

1/12, C12

assume two different compounds (X and Y) both made using different amounts of element A and fixed amount of B. law of multiple proportions state that

A/B in X = k*A/B in Y

assume compound X made using element A and B. law of definite proportions states that

A/B always remains constant no matter amount of compound X

can amount of protons equal amount of neutrons in an isotope? (yes/no)

yes

what equipment made discovery of electron?

cathode-ray tube

why did people know cathode-ray was negative?

because negative magnet repelled cathode ray

how did people know cathode-ray was composed of electrons?

cathode-ray was present with and without gas

who discovered the nucleus?

Rutherford

what did gold foil do to alpha particles?

deflected a few of them

what did gold foil experiment prove?

atom is mostly nucleus

who made the electron model?

Bohr

what does law of multiple proportions state?

if 2 or more elements present, ratio is always whole number

who invented atomic theory?

John Dalton

what are the six fundamentals of atomic theory?

all matter = atoms, atoms of same elements same and different elements different, atoms are smallest unit possible, atoms of different elements combine in whole number ratios for compounds, atoms are rearranged in reactions

can the amount of neutrons in each atom differ in a sample of an element?

yes

what kind of particle is beta ray?

high energy electron

what kind of particle is gamma ray?

high energy radiation?

what kind of particle is alpha particle, and what is its charge?

helium nucleus with 4 amu, 2+