Atoms

Question 1

what are isotopes

Answer 1

atoms with the same number of protons (same element) with different number of neutrons

Question 2

what is the mass number of an element

Answer 2

no protons + no neutrons

Question 3

what is the atomic number of an element

Answer 3

the number of protons in 1 atom

Question 4

how can an electron move up an energy level

Answer 4

if it absorbs sufficient electromagnetic radiation

Question 5

how small is a nucleus compared to a whole atom

Answer 5

around 10,000 times smaller

Question 6

what is the radius of an atom

Answer 6

around 1x10(-10) m

Question 7

describe J.J. Thompson’s plum pudding model

Answer 7

a sphere of positive charge with negative electrons embedded in it

Question 8

describe the basic structure of an atom

Answer 8

a nucleus containing protons and neutrons, around which electrons orbit in fixed energy shells

Question 9

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

Answer 9

-most of the mass of the atom is concentrated in nucleus (mostly empty space)
-nucleus is positively charged