chemistry test 2

Question 1

who created the term atoms to describe particles that could not be cut?

Answer 1

Democritus

Question 2

who was a famous pholisopher that disagreed with democritus’ theory?

Answer 2

aristotle

Question 3

_________- tried to find a way to create gold, but contributed little to modern chemistry

Answer 3

alchemists

Question 4

who is known as the father of modern chemistry? how was he able to make such significant contributions?

Answer 4

1. Antoine Lavoisier
2. he made very precise measurements and used the scientific process

Question 5

List Dalton’s postulates (4)

Answer 5

1. all matter is made up of atoms
2. atoms of same element are identical
3. atoms cant be created nor destroyed
4. combine in whole # ratios

Question 6

what did the cathode tube experiment prove? Who performed this experiment?

Answer 6

it proved that electrons exist and are negative, they also move towards positive charge. J.J. Thompson was the person who performed this experiment.

Question 7

What did the gold foil experiment prove? who performed this experiment?

Answer 7

it proved that atoms have a nucleus because only some particles bounce back because they hit a large nucleus. Ernest Rutherford performed this experiment.

Question 8

who discovered the neutron?

Answer 8

James Chadwick

Question 9

what did Millikan do?

Answer 9

discovered exact charge and mass of the electron (thompson only found the ratio)

Question 10

what did de broglie discover?

Answer 10

electron clouds and wave model

Question 11

the current model of an atom is the __________ model.

Answer 11

wave model

Question 12

what is the difference between atomic mass and mass number?

Answer 12

mass number is protons + neutrons. Atomic mass is the average of many different isotopes

Question 13

How do you find the number of protons and electrons for an element?

Answer 13

they are equal to the atomic number

Question 14

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

Answer 14

mass number - atomic number

Question 15

how do you find the mass number for an element?

Answer 15

protons+neutrons

Question 16

electrons have ____ charge and __ mass and are found in ______ around the nucleus

Answer 16

negative, no mass, orbit

Question 17

protons have _______ charge and are found in the ______

Answer 17

positive, nucleus

Question 18

_______ have the same number of protons but vary in the number of neutrons

Answer 18

isotopes

Question 19

why was the gold penny lab performed? how does it relate to this chapter?

Answer 19

the penny was coated with zinc and turned silver in color. The brass was made to look like gold. This is inline with what some alchemists tried to do to make fake gold

Question 20

how do you find the atomic number of an element?

Answer 20

mass number - neutrons