Chemistry Formulas Ch 2

first formulas and things you need to know for the quiz on September 5th

A/Z

A= mass number

Z= atomic number(often omitted)

Z

Z= atomic number

number of protons

A

A= atomic mass

A=protons+neutrons

A-Z

used to find number of neutrons

Atoms acquire energy by gaining or losing…

electrons

Negatively charged atoms are called … and they are formed when an atom … an electron

anions, gain

Positively charged atoms are called … and they are formed when an atom … an electron

cation, loses

Isotopes are atoms with the same … but different … since they have a different number of …

Z(atomic number), A(atomic mass), neutrons

How do you find the % abundance of an isotope?

abundance will always equal 100%, subtract from 100 if given the abundance of one of the isotopes

(mass1 x abundance1)+(mass2 x abundance2)=?

amu(average atomic mass) of 2 isotopes

Elements arranged in horizontal rows refer to … which are organized by increasing …

periods, atomic number

a vertical column of elements is a …

group

Main group elements

1A-7A

Transition Metals

3B-8B +1B

group 1A elements are called …

Alkali metals

group 2A elements are called …

Alkaline Earth metals

group 5A elements(N, P, As, Sb, Bi) are called …

Pnictogens

group 6A elements(O, S, Se, Te, Po) are called …

Chalcogens

group 7A elements are called …

Halogens

group 8A elements are called …

Noble gasses

an element is composed of … of the same …

atoms, type

a … is a substance composed of 2 or more different types of … arranged in a specific ratio and connected by chemical bonds.

*the character of each element is lost when forming this

compound, atoms

a … is a combination of two or more … in a specific arrangement held together by chemical bonds

molecule, atoms

diatomic molecules are …

molecules made up of two atoms chemically bound together via covalent bonds, meaning they share electrons to remain stable

ionic compounds are made when …

ex) NaCl

there is an electron transfer between atoms, typically when a metal atom transfers an electron to a non metal atom

metals tend to … electrons and become positively charged …

lose, cations

nonmetals tend to … electrons and become negatively charged …

gain, anions

Because an ionic compound has a neutral charge, the sum of the charge must be …

zero

molecular formulas use chemical symbols and subscripts to show how many … there are in each type of molecule

atoms

structural formulas use … to show how the atoms are connected in a molecule

lines

empirical formula shows how many … are actually present in the simplest whole number ratio of … in a compound

atoms, atoms/ions

1 mole=

6.022 × 10²³(avogadro’s number)

molar mass in grams is equivalent to …

(A)atomic mass(amu)

how to find #atoms when given #moles

#moles= #atoms/6.022 × 10²³

how to find #moles

#moles=mass/molar mass

how to find mass when given molar mass

mass= molar mass x #moles

how to find #atoms

#atoms= (6.022 × 10²³) x #moles of atoms

how is molar mass denoted?

g/mol