Periodic table + alkali metals + noble gases

How is the periodic table organized?

By increasing atomic number (no of protons that increase by 1, more protons = heavier mass).

Periods that tell us the number of electron shells.

Groups tell us how many outer electrons (electrons in the outer shell) the element has. Elements in the same group react very similarly.

Why do elements in the same group have similar chemical properties?

They have the same number of valence electrons (electrons in the outer shell). These are the ones involved in chemical reactions and therefore determine the chemical behavior of an element.

Properties of metals and non-metals: heat and electricity

Metals are good conductors of heat and electricity (thermal energy) because they have delocalized (free to move) electrons between the atoms.

Non-metals are bad conductors of heat and electricity because they don't ve delocalised electrons or mobile ions. Exceptions exist like graphite and silicon

Properties of metals and non-metals: oxygen

When metals react with oxygen they can form metal oxides. If a metal oxide 8 soluble in water it will dissolve to form an alkaline. Metal oxides are usually bases (they neutralise acids).

When non-metals react with oxygen they form non-metal oxides. Non-metal oxides are usually acidic.

What are the properties of noble gases?

Colourless gases at room temp

Unreactive.

Density + boiling and melting points increases going down the group.

All noble gases are monatomic

Why are noble gases inert?

They have a full outer shell therefore do not have a tendency to lose, gain or share electrons in a chemical reaction as they are already stable (stable electronic configuration.

What are the properties of alkali metals? How do these properties change as you go down the group? State which ones are different or similar to typical metals.

Different from typical metals:

- They are soft (for a metal) and can be cut with a knife. Softness increases going down the group.

- They have low melting and boiling points. These decrease going down the group.

- They have low density, density increases going down the group.

- They are very reactive. Reactivity increases going down the group.

Similar to typical metals:

- They are good conductors of heat and electricity.

- They are shiny when freshly cut.

What happens to alkali metals when in contact with the air?

They react with the oxygen (water vapor, just put oxygen) from the air, forming metal oxides which is a dull, matte grey colour coating.

How can we keep alkali metals from reacting with the air?

Keeping them in a sealed jar with oil.

Give me the word and chemical equation when lithium reacts with oxygen.

Lithium + oxygen ~> lithium oxide

4Li(s) + O2(g) ~> 2Li2O(s)

How does lithium react with water?

Fizzes (gives off gas), floats (less dense than water)/moves on the surface of water, appears to have dissolved (?).

Does not melt.

How does sodium react with water?

Fizzes rapidly giving off a gas, melts to form a ball, moves around on the water surface, floats.

How does potassium react with water?

Fizzes, melts (difference) straight away dissolving (similarity), burns with a lilac flame, reacts very quickly (vigorous reaction).

Why does potassium appear dull just after being taken from its container?

Because it is so reactive that it is difficult to keep it from reacting with the air even in oil.

What is the word/chemical equation for the reaction between alkali metals and water? Example using lithium.

Lithium + water ~> lithium hydroxide + hydrogen

2Li(s) + 2H2O(l) ~> 2LiOH(aq) + H2(g)

If the universal indicator was previously green, after adding the alkali metals into the water what colour would it turn and what would the pH be? Why?

Blue and pH 12-14 because they are alkaline/bases