Chapter 4

what is the difference between 0-16 and 0-17

0-16; eight neutrons 0-17; nine neutrons

what is an electron cloud

a visual model of the most likely locations for electrons in an atom

what did dalton notice that all compounds have in common

all fixed compostion, made up of atoms of more than one element they always form a ratio of their masses as whole numbers

what are isotopes

atoms of the same element that have a different number of neutrons and different masses

democritus believed that all matter consisted of extremely small particles what did he call these particles why did he use this term

atomus; uncut, divisible

explain why it isn't possible for an atom to have a mass number ten and an atomic number of 12

because the mass has to at least be the atomic number

an electron can or cannot exist between energy levels

cannot

what subatomic particle had thomson discovered

electron

bohr's model of the atom was improved as scientists made further discoveries what model do scientists use to describe how electrons move around the nucleus

electron cloud model; space around the nucleus where electrons are found

describe the bohr model of the atom

electrons orbit or rotate like planets around the sum

if atoms are neutral, the number of is equal to the number of

electrons;protons

the atoms of any given always have the same number of protons

element

determine the atomic number, mass number, number of protons, number of electrons and number of neutrons for the following atoms; Francium- 223, Bi- 209, P- 31

fr bi p p; 87 p; 83 p; 15 n; 136 n; 126 n; 16 e; 87 e; 83 e; 15

what is the atomic number

it equals the number of protons in the atom of that element

determine the number of electrons in each energy level for krypton and silicon

krypton silicon p; 36 p; 14 n; 48 n; 14 e; 36 e; 14

how do objects with the same charge behave when they come close to one another opposite charge

like; repel opposite; attract

describe the plum pudding model

negative particles in the mass of positively charged mass

which subatomic particles have almost the same mass

protons and neutrons

name three subatomic particles

protons, electrons, and neutrons

what are their masses, locations and charges

protons; one nucleus, one neutron neutrons; zero nucleus, one negative neutron electrons; negative one nucleus, 1/1836 neutrons

thomson hypothesized that the beam in his experiment was a stream charged particles what happened to the beam when it passed by a positively charged plate

the beam bent; it attracted

rutherford predicted the results of his gold foil experiment based on thomson's model of the atom some of the results could not be explained using thomson's model of the atom what new model was proposed by rutherford

the gold foil experiment; a model with a nucleus

compare the mass and volume of the nucleus to the total mass and volume of an atom

the mass of an atom is in the nucleus; none of the volume ex. like a marble compared to a football stadium

what are energy levels

the possible energies that electrons in an atom can have

what is the mass number

the red number; sum of protons and neutrons together

explain why scientists accepted dalton's atomic theory but not the idea of an atom proposed by the greek philosophers

they accepted his theory because he had proof

what is the maximum number of electrons in the first four energy levels

two,eight,eighteen and thirty two