Chapter 2: Atoms, Elements and Matter

Question 1

-pure substance that cant be broken down into simpler substances by ordinary chemical or physical techniques

Answer 1

element

Question 2

anything that occupies space and has mass

Answer 2

matter

Question 3

what four elements make up weight of living organisms?

Answer 3

C, H, O, N

Question 4

vital for normal biological functions

-occurs in quantities less than 0.01%

Answer 4

trace elements

Question 5

the smallest units that retain the chemical and physical properties of an element

Answer 5

atoms

Question 6

atoms combine chemically in fixed numbers and ratiors

Answer 6

molecules

Question 7

standard symbols for elements and subscripts for the number of atoms of each element

Answer 7

formula

Question 8

amount of matter in an object

Answer 8

mass

Question 9

measure of the pull of gravity on an object

Answer 9

weight

Question 10

molecules whose component atoms are different

Answer 10

compounds

Question 11

layered groups of electrons around the nucleus

Answer 11

electron shell

Question 12

an element with a full outer electron shell

Answer 12

noble gas

Question 13

nuclei of some isotopes are unstable and break down giving off particles of matter and energy

Answer 13

radioactivity

Question 14

decay transforms the unstable, radioactive isotope into an atom of another elemt

Answer 14

radiosotope

Question 15

isotopes that are used in biological research

Answer 15

tracers