chemistry - unit 2 - section 2 : group 2 and group 7 elements

Give the equations for extracting titanium from its ore.

TiO_2(s)+2Cl_2(g)+2C(s)\to TiCl_4(l)+2CO(g)

TiCl_4(l)+2Mg(s)\to Ti(s)+2MgCl_2(s)

Why is titanium ore not heated with carbon?

Brittle, poor engineering material.

Give the wet scrubbing reaction for quicklime.

CaO(s)+SO_2(g)\to CaSO_3(s)

Which chemical is ingested to prepare for a gastrointestinal x-ray scan?

bariumsulfate

Give a reason why it might be surprising that patients ingest a compound of this particular alkaline earth metal.

toxic

Give a reason why this compound is safe to ingest.

Insoluble, low solubility.

test for sulfate ions

we add barium chloride . If sulfate ions are present, barium sulfate will form. This product can be observed as a precipitate or solid due to its very low solubility . However, first, the solution is acidified to remove carbonate ions.

Describe the bonding in magnesium

Attraction between (lattice of) Mg2+ ions

And delocalised electrons

Explain, in terms of structure and bonding, why magnesium chloride has a high melting point.

(Giant) ionic lattice / lots of Mg2+ and Cl– ions

Strong (electrostatic) forces of attraction

Between Mg2+ and Cl– ions

Explain why the melting point of magnesium is higher than the melting point of sodium

Mg2+ has a higher charge than Na+

Stronger attraction to delocalised sea of electrons / stronger metallic bonding

Explain why the second ionisation energy of calcium is lower than the second ionisation energy of potassium.

In Ca(+) (outer) electron(s) is further from nucleus
More shielding (in Ca+ )

Why isotopes of strontium have identical chemical properties

Same electronic configuration

Explain why the melting point of calcium sulfate is high.

Strong attraction

Between positive and negative ions