Question

nova video questions: hunting the elements
physical science - coach barry

1. why is an alkali metal element like sodium (na) so reactive? (45:00)
2. what does chlorine (cl) do for sodium (na⁺)? what tasty substance is produced when this happens? (48:00)
3. what powers explosions and fire? (55:00)
4. what elements are basic to all living things? (59:00)
5. why is carbon (c) so good for forming the structure of life? (1:06:00)
6. what are at least three (3) other elements that are used for life functions and what are their uses? (1:12:00)
7. why are cyanobacteria from places like volcanic pools so important for the production of oxygen in our atmosphere? (1:17:00)
8. what was the original element formed moments after the big bang? what then created higher order elements? (1:19:00)
9. how does silicon shape our technological reality? (1:22:00)
10. how are rare earth elements like neodymium (nd) important to our technological world? (1:27:00)
11. what is an isotope like carbon - 14? (1:42:00)
12. how can an isotope like carbon - 14 be used to date dead organisms? (1:44:00)
13. what is an unstable radioactive isotope? (1:46:00)
14. why dont man - made radioactive elements exist for very long? (1:58:00)

Explanation:

1. Sodium has one valence electron in its out - most shell. It readily donates this electron to achieve a stable electron configuration, making it highly reactive.
2. Chlorine accepts sodium's valence electron. The reaction between sodium and chlorine produces sodium chloride (table salt).
3. Oxidation reactions, often involving oxygen, power explosions and fire. Oxygen provides the necessary oxidizing agent for combustion.
4. Carbon, hydrogen, oxygen, and nitrogen are basic to all living things. They form the building blocks of organic molecules like carbohydrates, proteins, lipids, and nucleic acids.
5. Carbon can form four covalent bonds, allowing it to create long - chain, branched, and ring - shaped molecules. Its ability to bond with itself and other elements makes it ideal for forming life's structures.
6. Calcium is important for bone structure and muscle function. Iron is used in hemoglobin to transport oxygen in the blood. Potassium is involved in nerve impulse transmission and maintaining fluid balance.
7. Cyanobacteria are photosynthetic. They use sunlight, water, and carbon dioxide to produce oxygen through photosynthesis, contributing significantly to the Earth's oxygen supply.
8. Hydrogen was the original element formed after the Big Bang. Nuclear fusion in stars creates higher - order elements.
9. Silicon is the basis of semiconductors. Semiconductor chips made of silicon are used in computers, smartphones, and many other electronic devices, shaping our technological reality.
10. Neodymium is used in powerful permanent magnets. These magnets are crucial in electric motors, generators, and magnetic resonance imaging (MRI) machines.
11. Carbon - 14 is an isotope of carbon. It has 6 protons and 8 neutrons (while the common carbon - 12 has 6 neutrons). It is radioactive.
12. Carbon - 14 is taken up by living organisms during life. After death, it decays at a known rate (half - life of about 5730 years). By measuring the remaining amount of Carbon - 14, the age of a dead organism can be estimated.
13. An unstable radioactive isotope is one that spontaneously emits radiation as it decays to achieve a more stable state.
14. Man - made radioactive elements are highly unstable. They decay quickly into more stable elements, so they don't exist for long.

Answer:

1. Sodium has one valence electron and readily donates it to achieve stability.
2. Chlorine accepts sodium's valence electron; sodium chloride is produced.
3. Oxidation reactions, often with oxygen, power explosions and fire.
4. Carbon, hydrogen, oxygen, nitrogen are basic to living things.
5. Carbon can form four covalent bonds and complex molecules.
6. Calcium for bone structure, iron for oxygen transport, potassium for nerve function.
7. Cyanobacteria are photosynthetic and produce oxygen.
8. Hydrogen was the first element; nuclear fusion in stars creates higher - order elements.
9. Silicon is the basis of semiconductors used in electronics.
10. Neodymium is used in powerful magnets in various devices.
11. Carbon - 14 is a radioactive isotope of carbon with 8 neutrons.
12. Carbon - 14 decays at a known rate and can be used for dating.
13. An unstable radioactive isotope emits radiation as it decays.
14. Man - made radioactive elements are highly unstable and decay quickly.