# Alkali, Alkali Earth, and Noble Gases

Skills to Develop

• Explain some facts about alkali metals, alkali earth metals, and noble gases.
• Apply the theories you have learned regarding the periodic table of chemical elements to explain the trends in properties of these elements.

## Alkali, Alkali Earth, and noble gases

Here is one of the nonsensical ways of remembering the Group I and Group II elements.


Group 1:  H  Li Na K  Rb Cs  Fr

Group 2:     Be Mg Ca Sr Ba  Ra


For the moment, please read your text on these elements. This page is still under construction, but some questions have been made up to test your skills.

## Confidence Building Questions

1. What is the most abundant element in the universe?

Hint: 92% of the mass of the sun is hydrogen.

2. What is the most abundant element in the Earth's crust?

Hint: More than 90% of the Earth's crust is silica.
Silica is $$\ce{SiO2}$$. Quartz and sand are typical silica, and silicon oxide is an important ingredient of many other minerals.

3. By what industrial process is hydrogen produced?

Hint: Using a nickel catalyst to convert light hydrocarbons to $$\ce{H}$$ and $$\ce{CO}$$.

4. What industrial application consumes the most amount of hydrogen?

Hint: The production of ammonia using the Haber process.

5. What is the name for the compound $$\ce{KH}$$?

Hint: potassium hydride

6. What is the oxidation state of hydrogen in the compounds $$\ce{NaH}$$ and $$\ce{LiAlH4}$$?

Hint: -1

7. What is the oxidation state of hydrogen in $$\ce{H2O}$$?

Hint: +1

8. Arrange the alkali metals in increasing order of their melting point.

Hint: Melting points increase in the order: $$\ce{Cs}$$ < $$\ce{Rb}$$ < $$\ce{K}$$ < $$\ce{Na}$$ < $$\ce{Li}$$

9. Arrange the alkali earth metals in decreasing order of their first ionization potential.

Hint: First ionization potential decreases in the order: $$\ce{Be}$$ > $$\ce{Mg}$$ > $$\ce{Ca}$$ > $$\ce{Sr}$$ > $$\ce{Ba}$$

10. Which metal has the highest density in the list: $$\ce{Li}$$, $$\ce{K}$$, $$\ce{Cs}$$, $$\ce{Ca}$$, $$\ce{Mg}$$, $$\ce{Ba}$$?

Hint: $$\ce{Ba}$$ has the highest density. Check their values up.

11. Arrange the noble gases in order of their atomic radii?

Hint: Atomic radii of the noble gases increase with atomic number: $$\ce{He}$$ < $$\ce{Ne}$$ < $$\ce{Ar}$$ < $$\ce{Kr}$$ < $$\ce{Xe}$$

12. Which alkali metal reacts with air to from a nitride?

Hint: $$\ce{Li}$$ is the only metal that reacts with air to form $$\ce{Li3N}$$.
$$\ce{Li3N}$$ is called lithium nitride. Nitrogen has an oxidation state of -3.

13. Sodium hydroxide is the seventh most manufactured chemical in the United States. How is the sodium hydroxide produced?

Hint: By electrolysis of concentrated aqueous sodium chloride (brine).

14. What is most of the sodium carbonate mined or produced in the United States used for?

Hint: For the production of glass; things may change in the future.

15. You have two solutions, a sodium nitrate and a barium nitrate. What chemical test will be able to tell you which is which?

Hint: Barium ions form a precipitate with sulfate ion.

$$\ce{Ba^2+ + SO4^2- \rightarrow BaSO4\: (insoluble)}$$

16. How is sodium produced?

Hint: By electrolysis of molten salt $$\ce{NaCl}$$.
Describe the chemical reaction in this process.

17. Which of the alkaline earth metals does not react with water (even hot water)?

Hint: Beryllium, $$\ce{Be}$$, is stable towards it, but $$\ce{Mg}$$ reacts with hot water.

18. When calcium nitride $$\ce{Ca2N3}$$ reacts with water, what are the products?

Hint: Calcium hydroxide and ammonia.
Write the equation for the described process.

19. What is the major chemical found in most calcium containing minerals?

Hint: Most calcium on Earth is calcium carbonate.

20. Do you know the chemical identity of calcium supplements from your pharmacy?

Hint: Calcium carbonate (the ingredient of sea and egg shells)

21. What is the chemical called quick lime?

Hint: Quick lime is $$\ce{CaO}$$, calcium oxide

22. Which has a higher atomic weight, $$\ce{K}$$ or $$\ce{Ar}$$?

Hint: Check them out from your periodic table.

23. How can you produce noble gases neon, argon, krypton, and xenon?

Hint: By fractional distillation of air.

24. Do you know what nobel gas compounds have been made? Give one as an example.

Hint: Xenon fluoride has been made.
Xenon fluoride has the formula: $$\ce{XeF4}$$.