Atomic structure and the periodic table - questions 41-60

How did Mendeleev change the early periodic table?

Mendeleev left gaps for elements that he thought had not been discovered and in some places, changed the order based on their chemical properties instead of atomic weight.

What is an ion?

When an atom loses or gains an electron, it becomes positively or negatively charged. It is now an ion.

What ions do metals form?

They lose electrons, forming positive ions.

What ions do non metals form?

They gai electrons, forming negative ions.

Name 4 physical properties of metals.

They conduct thermal energy and electricity, they are shiny, malleable and have a high melting point.

Where are non metals found on the periodic table?

Towards the top right.

In group 7 and group 0, describe the pattern in melting point as you go down the group.

As you go down group 7 and 0, the melting point increases.

Explain the pattern in melting point as you go down group 7 and 0.

Increases because the atoms get bigger in size, so there are more intermolecular forces of attraction and more energy is needed to overcome the forces.

Describe the pattern in melting point as you go down group 1.

As you go down group 1, the melting point decreases.

Why are atoms in group 0 stable?

They have a full outer shell and are therefore completely inert (unreactive).

Describe the pattern in reactivity as you go down group 1.

As you go down group 1, the reactivity increases.

Explain the pattern in reactive as you go down group 1.

Increases because the atoms get bigger and have more shells. This means the outer electron is further from he nucleus and is more shielded. There is a weaker attraction between the nucleus and outer electron, so the outer electron is more easily lost.

What is the general equation for alkali metals reacting with water?

Alkali metal + water → alkali metal hydroxide + hydrogen.

What is observed when lithium reacts with water?

Lithium doesn’t melt, fizzing can be seen.

What is observed when sodium reacts with water?

Large amounts of heat are released faint sodium to melt. Hydrogen released catches fire and causes the ball of sodium to dash across the surface.

What is observed when potassium reacts with water?

Potassium entre into a shiny ball that dashes across the surface and hydrogen burns with a lilac coloured flame.

What happens when alkali metals react with oxygen?

They form metal oxides, producing a layer of dull oxide on the surface of the metal.

How is the reaction between alkali metals and oxygen prevented?

They are stored in oil to prevent them from reacting with oxygen in the air.

What happens when alkali metals react with chlorine?

They from chlorides which are all white crystalline solids that are soluble in water. E.g sodium + Charline → sodium chloride.

Describe the pattern in reactivity as you go down group 7.

As you go down group 7, reactivity decreases.