Transcript 2. What does this symbol mean?

1. What does this symbol mean?
corrosive
2. Sodium has this hazard symbol what precautions should you take
when using it?
Goggles, pick up
with tweezers, use a
safety screen
3. What does this mean?
toxic
4. What element does this
represent? sodium
Na
5. Which group is it in?
1
6. Which period is it in?
3
7. Which of these is the flame
colour for sodium chloride?
The yellow one
8. What can you say about the
spectrum for each element?
Each element has a different spectrum, it can be used to identify
the element.
9. How did they know that there was
an undiscovered element in the sun?
I’ve never seen
that yellow line
before when I’ve
been looking at
spectra.
There were
lines that
hadn’t been
seen
before in
other
spectra.
There must be
an element on
the sun we
haven’t
discovered
yet. Let’s call
it helium after
the Greek
name for the
sun.
10. What is the name of the group
which this element belong to?
The Halogens (Group 7)
Cl
11. What does Cl2 tell you? 2 atoms in a
chlorine molecule.
12. Why am I added to water at
the swimming pool? To kill bacteria.
13. What do these alkali metals
have in common? Soft, silvery, one electron in outer
shell, react with water to make hydrogen and an alkaline solution, all
end in ium, metals ….
Li
Rb
14. Do they become more or
less reactive as you go down
the group? more
15. Name the two
products:
Cs
Sodium + water  sodium
Na
K
hydroxide + hydrogen
16. Inside an atom there are
neutrons. What else are there?
Protons and electrons
17. What word do we use to
describe a charged particle like
Na+? ions
18. Element or compound?
Compound because the atoms aren’t all the same.
19. Atom, molecule or ion? It is a
molecule – a group of atoms joined together.
H2
20. Atom, molecule or ion? Ion
because it has a charge.
Cl
21. If my electron configuration is
2,8,1; what group am I in? 1 because there
is one electron in the outer shell.
22. What period am I in? Period
3 because 3 shells are used.
23. Why does sodium chloride
have a high melting point? There is a strong
attraction between the + and – ions and a lot of energy is needed to pull
them apart.
24. Why are salt
crystals cubic? The
ions are arranged in a regular way –
in a lattice.
25. Why don’t salt
crystals conduct
electricity? The ions are
fixed in position and can’t move
around.
26. Why does melted salt or salt
solution conduct electricity?
The ions can move
around and carry
current.
27. What’s the formula?
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Water
Sodium chloride
Hydrogen
Chlorine
Sodium hydroxide
H2O, NaCl, H2, Cl2, NaOH
28. Give any trends.
Name
Hardness
Density
g/cm3
Melting point
oC
Lithium
Fairly hard
to cut
0.53
180
Sodium
Easy to cut
0.97
98
Potassium
Very easy to
cut
0.86
64
As you go down the group, the elements get softer, there is no
pattern in density, the melting point decreases.
29. What do they mean?
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•
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•
H2O (l)
Na (s)
Cl2 (g)
NaCl (s)
NaCl (aq)
Water is a liquid, sodium is a solid, chlorine is a gas, sodium chloride
solid and sodium chloride solution.
30. What happens to a chlorine
atom when it reacts?
Cl
2.8.7
The atom will gain an electron to get a full outer
shell. It will become Cl-
31. What happens to a sodium
atom when it reacts?
Na
2.8.1
The atom will lose an electron to get a full outer
shell. It will become Na+
32. Give the ion for:
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Sodium
Magnesium
Aluminium
Fluorine
Oxygen
Na+ (Group1)
Mg2+ (Group 2)
Al3+ (Group 3)
F- (Group 7)
O2- (Group 6)
33. Which are salts?
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Sodium
Chlorine
Sodium chloride
Potassium bromide
Magnesium
iodine
Salts are made when you react a metal with a non-metal.