p7: atoms

Question 1

describe the basic structure of an atom

Answer 1

nucleus containing protons and neutrons, around which electrons orbit in fixed energy levels (shells)

Question 2

describe the plum pudding model of the atom

Answer 2

sphere of positive charge with negative electrons embedded in it

Question 3

what charges do protons, neutrons and electrons carry

Answer 3

protons = positive
neutrons = no charge
electrons = negative

Question 4

why do atoms have no overall charge

Answer 4

equal numbers of positive protons and negative electrons

Question 5

what is the radius of an atom

Answer 5

around 1x10 -10 m

Question 6

how small is the nucleus compared to the whole atom

Answer 6

around 10 000 times smaller

Question 7

how can an electron move up an energy level

Answer 7

absorb sufficient electromagnetic radiation

Question 8

what is ionization

Answer 8

process which adds or removes electrons from an atom

Question 9

what is formed if an atom loses an electron

Answer 9

positive ion

Question 10

how does an atom become a negative electron

Answer 10

gains 1 or more electrons

Question 11

what is the atomic number of an element

Answer 11

number of protons in one atom of the element

Question 12

what is the mass number of an element

Answer 12

number of protons + number of neutrons

Question 13

which particle do atoms of the same element always have the same number of

Answer 13

protons

Question 14

what are isotopes

Answer 14

atoms of the same element

Question 14

what were the 2 main conclusions from the alpha particle scattering experiment

Answer 14

nucleus is positively charged
most of the mass of an atom is concentrated in the nucleus