atomic theory

Question 1

what is an atom?

Answer 1

the smallest particle of an element that give the element their properties

Question 2

what is an atomic theory?

Answer 2

the study of the nature of atoms and how they combine to form all types of matter

Question 3

why is the atomic theory important?

Answer 3

• to help us understand why there are different types of atoms
• to explain how atoms combine to form matter

Question 4

according to john dalton, what was all matter made of?

Answer 4

small, indivisible particles called atoms

Question 5

according to john dalton, were all atoms of an element identical?

Answer 5

yes

Question 6

what did john dalton discover about different elements?

Answer 6

different elements have different properties

Question 7

john dalton found that atoms of different elements could combine in specific ways to form what?

Answer 7

new substance

Question 8

what did john dalton’s atomic model look like?

Answer 8

“billiard ball model”

an atom is a solid, indivisible sphere

Question 9

what did jj thomson experiment with?

Answer 9

electric currents in glass tubes

Question 10

what was jj thomson able to produce?

Answer 10

streams of negative charged particles from nonradioactive atoms

Question 11

what did jj thomson conclude

Answer 11

atoms must contain positive charges if they contain negative energy

Question 12

what did jj thomson’s atomic model look like?

Answer 12

“plum pudding model”

an atom is a postive sphere with negative electrons scattered throughout it

Question 13

what did ernest rutherford experiment with?

Answer 13

a gold foil barrier, with positively charged particles shot at it

Question 14

what did ernest rutherford expect to see?

Answer 14

all particles passing through the foil

Question 15

what actually happened in ernest rutherford’s experiment?

Answer 15

most particles went through the foil, but some deflected off

Question 16

what did ernest rutherford conclude?

Answer 16

atoms are mostly empty; the nucleus is positive and contains most of the atom’s mass

Question 17

what did ernest rutherford’s model look like?

Answer 17

“nuclear model”

• an atom is mostly empty space
• has a small positive nucleus, surrounded by negative electrons

Question 18

what did niels bohr predict?

Answer 18

electrons surrounded the nucleus in specific energy levels

Question 19

what were niels bohr’s energy levels called?

Answer 19

“shells”

Question 20

each shell could only contain what?

Answer 20

a specific number of electrons

Question 21

the maximum number of electrons that could exist in each of the first 3 shells is what?

Answer 21

2/8/8

Question 22

electrons could jump between shells by what?

Answer 22

gaining or losing energy

Question 23

what did niels bohr’s atomic model look like?

Answer 23

“planetary model”

electrons are in specific orbits

Question 24

what did james chadwick discover?

Answer 24

the nucleus contains neutral particles (neutrons) and positively charged particles (protons)

Question 25

james chadwick discovered that each neutron in an atom has about the same ___ but the neutron carries no ____?

Answer 25

• mass

- electrical charge

Question 26

according to the the quantum mechanical model, electrons do NOT exist as what?

Answer 26

tiny points inside an atom

Question 27

according to the the quantum mechanical model, electrons exist in what?

Answer 27

specific energy levels

Question 28

electrons surround what, resembling a cloud?

Answer 28

the positively charged nucleus

Question 29

what does today’s quantum mechanical model look like?

Answer 29

a cluster of particles