definitions: states of matter and chemical formulae

Question 1

molecule

Answer 1

Molecules are groups of two or more atoms chemically joined together. They can be elements.

Question 2

isotope

Answer 2

Atoms of the same element that contain the same number of protons but different number of neutrons

Question 3

Why do all the isotopes of an element undergo the same chemical reactions?

Answer 3

Chemical reactions involve electrons and all isotopes have the same number of electrons on the outer shell.

Question 4

structure of an atom

Answer 4

There is a nucleus in the middle that contains positively charge protons and neutrally charge neutrons. It is surrounded by shells that are accompanied by negatively-charged electrons

Question 5

atomic number

Answer 5

= number of protons

Question 6

atomic mass

Answer 6

= num of protons + num of neutrons

Question 7

the periodic table is

Answer 7

An arrangement of elements in order of increasing atomic number

Question 8

ions

Answer 8

Atoms or groups of atoms that are charged due to the loss or gain of electrons