Chemistry H Ch. 2

what are the polyatomic ions?

nitrate, carbonate, sulfate and phosphate

what does cation mean?

positive, losing electrons

what does anion mean?

negative, gaining electrons

what are the 4 parts to the Atomic Theory Timeline?

1. atoms are tiny invisible particles

2. atoms of 1 element are all the same

3. atoms of all elements are different

4. compounds form by combining atoms

who created the Atomic Theory Timeline?

John Dalton

what did the Cathode Ray discover?

the electron

what did the Milkan Oil Drop determine

the charge of an electron

what did the Gold Foil experiment discover?

the nucleus

what were the 3 conclusions to the Gold Foil experiment?

1. there are positive particles in the center

2. there is a small, massive region in the center

3. most of the atom is empty space

what are the 2 conclusions from the Cathode Ray experiment?

1. the light beam must be negatively charged because it draws to the positive charge

2. everything else in the atom must be positive

what is the equation for finding average atomic mass?

(% abundance)(mass) + (% abundance)(mass)

what is the mass number?

the number of protons and neutrons

what is the atomic mass?

the weight of the proton and neutrons

what is an isotope?

atoms of the same element but have different masses (# of neutrons)

what is average atomic mass?

the weighted average of the atomic masses of the naturally occurring isotopes

properties of alkali metals

reactive, explosive, produces hydrogen gas when mixed with water

properties of alkaline earths

found in the body, used for fireworks, not as reactive as. alkali metals

properties of halogens

most reactive non-metal, have 7 electrons and gain 1 when reacting

properties of noble gases

stable, don't bond, don't cause reactions, are used in neon lights

properties of transition metals

colorful, cancer causing, no clear laws

what is the atomic number?

the number of protons

all atoms of the same element have _____ number of protons

the same

if the number of electrons change the ____ changes

charge

if the number of neutrons changes the ____ changes

atomic mass

if the number of protons changes the ____ changes

element

T/F: atoms of the same element have to have the same number of neutrons

F

How do you find the mass number?

# of protons + # of neutrons

Can mass number be found on the periodic table?

no

atoms of the same element that have different numbers of neutrons

isotope

how do you find the number of neutrons in an element?

mass number - # of protons

if an atom has 14 protons and 20 neutrons, what's its atomic number?

14

if an atom has 14 protons and 20 neutrons, what's its mass number?

34

what is 1 amu equal to?

1/12 the mass of a carbon-12 atom

what is average atomic mass?

the weighted average of the atomic masses of the naturally occurring isotopes of an element

neutral atoms have the same number of

protons and electrons

in Rutherford's experiment, alpha particles...

were used to bombard thin metal foil

Whose series of experiments identified the nucleus of the atom?

Chadwick

Because any element in the cathode produced electrons, scientists concluded that...

all atoms contained electrons

Experiments with cathode rays led to the discovery of the

electron

the rays produces in a cathode tube are

deflected away from a negative plate

the atomic theory proposed by Dalton had been

expanded and modified

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