Download Atoms Combine to Make Compounds

Atoms Combine to Make Compounds
Learning Goals:


I will be able to define pure substance, element, compound, and molecule.
I will be able to use subscripts to describe how many atoms make up a compound.
Pure Substances:
 A pure substance is matter that is made up of only one type of particle.
 An element has only one type of atom
 A compound has 2 or more atoms that are joined chemically by a bond.
Found on
Pure
Substance
Made from
from the PT
Element or Compound?
CaCO3
Au
AuO
Br2
How We Represent Chemical Compounds
 Subscripts are ____________________ numbers that tell us the number of each type of atom in
a compound.
 If there is no number stated then it automatically means there is ______________ atom
present.
 Coefficients are _____________numbers in front of formulas that tell us we have more than 1
molecule present.
Counting Atoms
 Every Capital Letter represents a new atom…it may be helpful to put lines between the element
symbols.
 State each element’s name (use the periodic table)
 State the number of each atom present (using the subscripts).
 Examples:
CaBr2
MgCO3
Be(OH)2
2NaCl
Questions:
Directions for each problem
1) write down the different elements in each compound.
2) write down how many of that particular atom there are
3) how many atoms are there total in the compound.
Examples:
A) MgCl2
Mg – 1
Cl – 2
B) 5 ZnSO4
Zn – 5
3 total
S–5
O – 20
1) NaOH
2) 4 HNO3
4) 4 Li2O
5) 2 NaOH
7) 3 H2O
8) NaC2H3O2
3) MgCl2
6) Li2SO4
9) 3 Al2O3
30 total
10) NH4Cl
11) 5 ZnSO4
12) 7 C2S2
SUPER STAR CHALLENGE!
13) 2 Sr3(PO4)2
14) 4 Al(OH)3
16) 4 Al2(SO3)3
17) 2 (NH4)3PO4
15) Ca (C2H3O2)2
18) 4 Mg(OH)2