Chemistry Test Study Guide

A number is a significant figure if it is …

A number is a significant figure if it is …

-not a zero (4.5)

-a zero between non zero digits (5.008)

-a zero at the end of a decimal number (16.00)

-in the coefficient of a number written in scientific notation (5.70 × 10^-3)

A number is not a significant figure if it is …

-at the beginning of a decimal (0.0004)

used as a placeholder in a large number without a decimal point (850,000)

Rules for rounding of …

-If the digit to be dropped is 4 or less, then it and all following digits are simply dropped from the number

-If the first digit to be dropped is 5 or greater then the last retained digit of the number is increased by 1.

Rules of significant figures for addition and subtraction …

least digits after decimal

Rules of significant figures for multiplication and division

least number of significant figures

1 kilo = ?

10³

milli = ?

10^-3

centi = ?

10^-2

micro

10^-6

nano

10^-9

Fahrenheit to Celsius formula ?

C = (F-32) x 5/9

Celsius to Fahrenheit formula ?

F = (C x 9/5) +32

Formula for density ?

mass/volume

Formula for volume ?

Density/mass

Formula for mass ?

density x volume

Matter ?

Anything that occupies space.

Inpure substances are mixtures (homogenous & heterogenous). Heterogenous mixtures have different layers (water and sand). Homogenous mixtures do not (water and dye).

Pure: simple → elements→ Na, Cl, Fe complex→ compound→ H₂O, NaCl

Subatomic particles

protons, neutrons, electrons

Charge of protons?

positive

Charge of neutrons?

neutral

Charge of electrons?

negative

Molecules

2 or more different atoms

Compound

2 or more different elements

cation

positive ion (lose electrons)

anion

negative ion (gain electrons)

atomic number

number of protons and electrons

mass number

number of protons and neutrons

atomic mass

The weighted average of the masses of all isotopes of that element

“amu” stands for

atomic mass unit

avogadro’s number

6.023 × 10²³

What kind of ions do metals form?

cations

What kind of ions do nonmetals form?

anions

What are the 3 types of compounds?

Ionic, covalent, and acids

Covalent compounds

nonmental & nonmetal

Ionic compounds

metal & nonmetal, form positive and negative ions

Monoatomic ions examples

Na⁺² Ca⁺² Cl^- O^2-₄

Polyatomic ions examples

SO_4^-2 PO_4^3- CO_3^2-

what shape is the “s” orbital?

spherical

what shape is the “p” orbital?

dumbbell

what shape is the “d” orbital?

double dumbell

electrons on the outer shell are called?

valence electrons

how many electrons can the “s” orbital hold?

2 electrons

how many electrons can the “p” orbital hold?

6 electrons

how many electrons can the “d” orbital hold?

10 electrons

Metals have a __________ ionization energy

Low

Nonmetals have a ________ ionization energy

High

Metallic Character _________ as you go down the periodic table and __________ as you go across the periodic table

increases, decreases

atomic size _________ as you go down the periodic table and _________ as you go across the periodic table

increases, decreases

molar mass

the quantity in grams that equals the atomic mass of that element

Which of the following elements has the largest atomic size: Li, F, S, Na ?

Na

ionization energy _____ as you go down the periodic table and _______ as you go across the periodic table

decreases, increases

formula for finding atoms?

moles x avogadro’s number

formula for finding moles

number of atoms/avogadro’s number

OR

mass/molar mass