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Question 1

what did j.j thompson study?

Answer 1

he studied electrical discharges in partially evacuated tubes (cathode ray tubes), and postulated that the ray was a stream of negatively charged particles (electrons).

Question 2

what is a cathode ray tube?

Answer 2

the “rays” emanating from, the negative electrode(cathode) in a partially evacuated tube; a stream of electrons.

Question 3

what is the equation for the “charge to mass ratio” that thompson discovered, and what do the letters represent?

Answer 3

e/m = -1.76 x 10^8 C/g
“e” represents the charge on the electron in coulombs (C), and “m” represents the electron mass in grams.

Question 4

what is radioactivity?

Answer 4

the spontaneous decomposition of a nucleus to form a different nucleus.

Question 5

what is a gamma ray?

Answer 5

high-energy “light”

Question 6

what is a beta particle?

Answer 6

a high speed electron.

Question 7

what is an alpha ray?

Answer 7

alpha particles have a 2+ charge that is twice that of an electron, and its mass is 7300 times that of an electron.

Question 8

what was rutherford’s concept of the nuclear atom?

Answer 8

based on his experiment, he deduced that the nuclear atom has a dense center of positive charge with electrons moving around the outside.

Question 9

why do different atoms have different chemical properties if all atoms are composed of the same components?

Answer 9

the number of electrons possessed by a given atom greatly affects its ability to interact with other atoms, and as a result, the atoms of different elements (with different numbers of protons and electrons) show differing chemical behavior.

Question 10

what are isotopes?

Answer 10

atoms with the same number of protons but different numbers of neutrons.

Question 11

what is an atomic number, and how is it written?

Answer 11

the number of protons in an element is written as a subscript.

Question 12

what is a mass number, and how is it written?

Answer 12

the total number of protons and neutrons is written as a superscript.

Question 13

how do you find the protons and neutrons of an element?

Answer 13

the number of protons of an element is in the atomic number (electrons must be the same to reach electrical neutrality), and the mass number gives the total number of protons and neutrons.

Question 14

what are ions?

Answer 14

an atom or a group of atoms that has a net positive or negative charge because of one or more electrons being added or removed from a neutral atom.

Question 15

what is a cation?

Answer 15

a positive ion

Question 16

what is an anion?

Answer 16

an ion with a negative charge

Question 17

what was millikan’s experiment?

Answer 17

he used charged oil drops to determine the magnitude of the electron charge. with this and the charge-to-mass ratio determined by thompson, he was able to calculate the mass of the electron.