Download Criss-Cross Practice Worksheet

Name _________________________________________ Date ___________ Period _________
1) What are charges for ions of main group elements (group A elements) and group B metals?
all B groups
1A
2A
3A
4A
5A
6A
7A
8A
Examples
Na+
Mg2+
for 2) – 4):
Al
Sn2+
Sn4+
3+
a) anion
3-
N
2-
O
Cl
-
Ne
Fe2+
Fe3+
b) cation
2) A positive ion is called ___________
3) a negative ion is called ___________________
4) Metals form __________________s
5) Nonmetals usually form __________________s
5) Which elements do not form ions? ___________________________________
6) Explain why an ionic compound is neutral even though it is made from negative and positive ions.
________________________________________________________________________________
________________________________________________________________________________
7) – 12)
a) formula unit,
b) molecular formula
7) The chemical formula of an ionic compound is called _________________________
8) The lowest whole-number ratio of ions in an ionic compound is called _____________________
9) shows the kinds and numbers of atoms present in a molecule: ______________________
10) The chemical formula of a molecular compound __________________________
11) MgCl2 is an example of a(n) _________________________
12) CO2 is an example of a(n) _________________________
13) What is the charge of the ions formed from the following elements?
a) sulfur
S
________
d) Argon
Ar
________
b) fluorine
F
________
e) selenium
Se
________
c) beryllium
Be
________
f) nitrogen
N
________
1
7) Use the criss-cross method to write the formula units for the following combination of ions
(remember to check for smallest whole number ratio)
a) Fe2+
S2-
b) Co2+
I-
FeS
# of S atoms in formula __1___
# of Fe atoms in formula __1__
# of Co atoms in formula______
# of S atoms in formula ______
c) Ni3+
d) Be2+
Se2-
P3-
# of Ni atoms in formula _____
# of Se atoms in formula _____
# of Be atoms in formula______
# of P atoms in formula______
e) Ag+
f) Al3+
F-
H-
# of Ag atoms in formula______
# of F atoms in formula______
# of Al atoms in formula______
# of H atoms in formula______
g) Li+
h) K+
Cl-
# of Li atoms in formula______
# of Cl atoms in formula______
i) W6+
O2-
# of W atoms in formula______
# of O atoms in formula______
Se2-
# of K atoms in formula______
# of Se atoms in formula______
j) Ca2+
H-
# of Ca atoms in formula______
# of H atoms in formula______
2
Name _________________________________________ Date ___________ Period _________
1) What are charges for ions of main group elements (group A elements) and group B metals?
all B groups
1A
2A
3A
4A
5A
6A
7A
8A
+1
+2 +3 varies -3
Examples
Na+
Mg2+
Al3+
for 2) – 4):
a) anion
-2
-1
0
varies
Ne
Fe2+
Fe3+
2+
Sn
Sn4+
b) cation
N3-
O2-
Cl-
b) cation _3) a negative ion is called_ a) anion
4) Metals form b) cations
5) Nonmetals usually form ___ a) anions_
5) Which elements do not form ions? _____noble gases_____________
2) A positive ion is called
6) Explain why an ionic compound is neutral even though it is made from negative and positive ions.
The positive and negative charges of the
ions cancel out, thus the ionic compound is
neutral as a whole.
7) – 12)
a) formula unit,
b) molecular formula
a)_______________
8) The lowest whole-number ratio of ions in an ionic compound is called ____a)____________
9) shows the kinds and numbers of atoms present in a molecule: ____b)________________
10) The chemical formula of a molecular compound ____b)___________________
11) MgCl is an example of a(n) _____a)________________
12) CO is an example of a(n) _______b)________________
7) The chemical formula of an ionic compound is called _________
2
2
13) What is the charge of the ions formed from the following elements?
S -2
b) fluorine
F -1
c) beryllium Be +2
a) sulfur
Ar 0
e) selenium Se -2
f) nitrogen
N -3
d) Argon
3
14) Use the criss-cross method to write the formula units for the following combination of ions
(remember to check for smallest whole number ratio)
a) Fe2+
FeS
S2-
b) Co2+
divided by 2
I-
CoI2
# of S atoms in formula __1___
# of Co atoms in formula__1____
# of Fe atoms in formula __1__
# of S atoms in formula ___2___
c) Ni3+
Se2-
d) Be2+
Ni2Se3
P3-
Be3P2
# of Ni atoms in formula __2___
# of Be atoms in formula__3____
# of Se atoms in formula ___3__
# of P atoms in formula___2___
e) Ag+
F-
f) Al3+
AgF
H-
AlH3
# of Ag atoms in formula___1___
# of Al atoms in formula__1____
# of F atoms in formula____1__
# of H atoms in formula___3___
g) Li+
Cl-
LiCl
h) K+
Se2-
K2Se
# of Li atoms in formula__1____
# of K atoms in formula___2___
# of Cl atoms in formula__1____
# of Se atoms in formula___1___
4
i) W6+
O2-
W2O6
divide by 2
j) Ca2+
H-
CaH2
WO3
# of W atoms in formula____1__
# of Ca atoms in formula___1___
# of O atoms in formula____3__
# of H atoms in formula___2___
5