Ch.2

Rutherford

________ explained the results of the experiment by creating the nuclear model of an atom: most of the mass and the positive charge of the atom lies in a dense region called the nucleus.

Gamma

________ (γ)- High energy electromagnetic radiation (similar to x rays), no charge and no particles.

Thompson

________ proposed that atom is an uniform sphere with evenly distributed mass and electrons embedded like seeds in a watermelon.

Beta

________ (β)- consist of fast- moving electrically charged particles, high speed electrons that are radioactive, have a negative charge (1)-

Electrode

________: element or semiconductor that emits or collects electrons.

Gas phase

________ is converted to cations that are positively charged particles.

Scientist JJ Thompson

________ described cathode rays as streams of negatively charged particles that we know call electrons.

Alpha

________ (α)- consist of fast- moving electrically charged particles, positive charge (2+)

Democritus

________ and other early Greek Philosophers described that the world is made up of tiny particles called atomos.

Neutral

________- present in the nucleus- no charge.

Proton

________- present in the nucleus- 1+ charge.

Cathode Rays

________: radiation produced between electrodes when a high voltage is applied to electrodes in a glass tube.

Proton Charge

________ is +1.602 × 10^- 19.

Mass spectrometer

________ is used to accurately determine the atomic weight.

Atom

________ is composed of subatomic particles.

Compounds

________ are formed when atoms of one or more element combine.

equal number of protons

Every atom has ________ and electrons and therefore has no net electric charge*

Radioactivity

________: spontaneous emission of radiation.

Ions

________ are separated by mass.

Protons

________ determine which atom is which.

Atomic weight

________ is the average atomic mass of all the elements isotope.

Any water sample

________ will always have two hydrogen atoms and one atom of oxygen in a 2: 1 ratio.

beam

The ________ passes through between poles of a magnet causing the ion ________ to curve.

Law of multiple proportions

________: If two elements combine to form more than one compound, the masses of the two compounds are in the ratio of small whole numbers.

Rutherford

In 1910, ________ performed experiments by shooting a beam of α particles through a thin sheet of gold foil and recorded where the α particles hit.

Atoms

________ in an element can differ in the number of neutrons forming an isotope.

Cathode rays

________ originate at the negative electrode and then travel to the positive electrode.

Ions

________ pass through the grid and encounter two slits which only allow narrow beam of ions to pass.

Dalton Atomic Theory

created by John Dalton

Law of constant composition

In a given compound, the relative numbers of kinds of atoms are constant

Put in simpler terms

in a particular chemical compound, all samples of that compound will have the same elements in ratio

Example

Water will always be h2O

Any water sample will always have two hydrogen atoms and one atom of oxygen in a 2

1 ratio

Law of conservation of mass

The total mass of materials present in a chemical reaction before and after a chemical reaction is always the same

Law of multiple proportions

If two elements combine to form more than one compound, the masses of the two compounds are in the ratio of small whole numbers

Put in simpler terms

If two elements such as hydrogen and oxygen combine to form more than one compound like h2O (water) and H2O2 (hydrogen peroxide)

Cathode Rays

radiation produced between electrodes when a high voltage is applied to electrodes in a glass tube

Electrode

element or semiconductor that emits or collects electrons

Radioactivity

spontaneous emission of radiation

alpha (α)- consist of fast

moving electrically charged particles, positive charge (2+)

beta (β)- consist of fast

moving electrically charged particles, high speed electrons that are radioactive, have a negative charge (1-)

Rutherford explained the results of the experiment by creating the nuclear model of an atom

most of the mass and the positive charge of the atom lies in a dense region called the nucleus

atomic mass unit (amu)

since atoms have such incredible small masses to make it easier for us to understand 1 amu = 1.66054 * 10^-24 g

Example

naturally occurring carbon is composed of 98.93% carbon -12 and 1.07% carbon 13

The mass spectrum-

graph of the intensity of the detector signal vs. ion atomic mass