1st OCTOBER, 2009
4TH ESO
NAME:.................................................................................................
ELEMENTS AND COMPOUNDS
(50)
1. Copy and complete
10
There are 3 types of particle found inside atoms: a)......................, b)...................and c)...................
This table shows their mass and charge:
Sub-atomic particle
Charge
Mass (atomic
mass units)
proton
.........
..........
...................
0
1
..................
.......
0
The protons and neutrons are found in the .....................of the atom, called nucleus.
The .........................zoom around the nucleus in shells. The 1st shell, which is ...................the nucleus,
can hold..............electrons, whereas the 2nd and 3rd shells can hold ............electrons.
2. Answer the following questions.
a) What is the atomic number of an atom?
10
b) What is the mass number of an atom?
c) What is the atomic number of the atom below?. What is its mass number?
40
18
Ar
c) Give the number of protons, electrons and neutrons in the atoms below:
14
7
N
39
19
K
60
27
Co
236
92
U
d) What are isotopes?. Write an isotope for U.
e)
Describe (briefly) Rutherford´s "gold foil experiment".
f)
Which are the differences between ‘orbits’ and ‘orbitals’?
3. On the Periodic Table below
10
H
Li
Na
K
Rb
Cs
Fr
a)
Be
Mg
Ca Sc
Sr Y
Ba La
Ra
Ti
Zr
Hf
V
Nb
Ta
Cr Mn Fe
Mo Tc Ru
W Re Os
Co
Rh
Ir
Ni
Pd
Pt
Cu
Ag
Au
Zn
Cd
Hg
B
Al
Ga
In
Tl
C
Si
Ge
Sn
Pb
N
P
As
Sb
Bi
O
S
Se
Te
Po
F
Cl
Br
I
At
He
Ne
Ar
Kr
Xe
Rn
Draw a dividing line between metals and non metals. Then, identify halogens, alkaline metals and
noble gases
b) Complete the electron configuration for the next atoms and find how many electrons would they
need to be like a noble gas. Write the ionization reaction for each one of them.
Na (11):
Cl (17):
O(8):
Li(3):
S(16):
H(1):
c)
Which of the following species are isoelectric (same number of electrons)? Sc0, Ca+2; Cl-1; S-2; Ti + 4.
d) Write the correct electron configuration for argon. Name two positive and two negative ions that
have this configuration
4. About ionic bonding
20
a) What change in electron structure occurs when a sodium atom becomes a sodium ion? What change, if
any, occurs in the nucleus when the ion is formed?
c) When chlorine forms an ionic compound it gains one electron. What symbol is used to represent the
chloride ion formed in this way?
d) Explain why the formula for the compound formed when sodium and chlorine react is Na Cl and not
NaCl2
e) What does the information given tell you about the structure of each substance? Chlorine melts at 101ºC. Sodium chloride melts at 801°C.
f) Here are 3 metal ions lithium, Li+; calcium, Ca2+ and iron (III), Fe3+. Here are 3 non-metal ions:
fluoride, F-; iodide, I-; sulphide, S2-.
Draw a table, to show the formulas and names of the compounds between these metals and non-metals.
g) Which of these substances have ionic bonds?
Ammonia, NH3; Water, H2O; Copper (II) oxide, CuO; Zinc chloride, Zn Cl2; Lead (II) bromide, PbBr2;
Potassium fluoride, KF; Methane, CH4
How did you decide?
h) Calcium oxide is an insoluble ionic compound. Why do ionic compounds have high
melting points?
i) Describe, as fully as you can, the ions that are formed when atoms of these elements
react.
j) What must be done to the solid calcium oxide to make it conduct electricity? Suggest a reason for your
answer.
k) Copy and complete
………………………………compounds are made from metals and non-metals. Metals always form
.................... charged ions, and non-metals form ………………….... charged ions. These ions are
arranged in ………………….... ionic structures. Their crystals have ……………………..... melting
points and many will ................................. in water. They conduct………………………….. when molten
or when in solution, but not when they are……………………………….