Question

nova video questions: hunting the elements physical science - coach barry name: ____________ period: date: ____________ answer the questions that follow to the best of your ability. the questions are in chronological order. 1) where does an element take its identity from? (5:30) 2) how much gold (au) is extracted per ton of rock ore? (8:30) 3) how much does a gold (au) bar weigh and how much is it worth? (13:00) 4) why is copper (cu) so widely sought on the world market and new york mercantile exchange? (16:00) 5) what is copper (cu) combined with to make bronze? (18:00) 6) what makes metals like copper (cu) conductive to electricity? (20:00) 7) bronze is an alloy. what is an alloy and why are they preferable at times? (22:00) 8) how does the atomic arrangement of atoms lead to its crystal structure like was seen in the sample of bronze with gold (au) and tin (sn) atoms? (32:00) 9) what is the atomic number and what does the atomic number indicate? (34:00) 10) most of the periodic table is made of what type of elements? (35:00) 11) how did early chemists like mendeleev classify the elements? (38:00) 12) how is the periodic table structured with regard to elements with similar properties? (40:00) 13) what makes noble gases stable? (43:00)

Explanation:

1. An element takes its identity from the number of protons in its nucleus (atomic number).
2. Typically very small amounts of gold are extracted per ton of rock ore, often just a few grams.
3. A standard gold bar usually weighs around 12.4 kilograms. Its worth depends on the market - price of gold which fluctuates.
4. Copper is widely sought as it is a good conductor of electricity and heat, malleable, and has many industrial uses.
5. Copper is combined with tin to make bronze.
6. The presence of free - moving electrons in metals like copper makes them conductive to electricity.
7. An alloy is a mixture of two or more elements, where at least one is a metal. They can have improved properties like strength, durability compared to pure metals.
8. The regular and repeating pattern of atomic arrangement leads to a crystal structure. In bronze with gold and tin atoms, the different sized atoms fit together in an ordered way.
9. The atomic number is the number of protons in an atom's nucleus. It indicates the element's identity and its position in the periodic table.
10. Most of the periodic table is made of metals.
11. Early chemists like Mendeleev classified elements based on their atomic mass and recurring chemical properties.
12. Elements with similar properties are grouped in columns (groups) in the periodic table.
13. Noble gases are stable because they have a full outer electron shell, making them unreactive.

Answer:

1. The number of protons in its nucleus.
2. Usually a few grams.
3. Around 12.4 kilograms; worth depends on market - price of gold.
4. Good conductor of electricity and heat, malleable, many industrial uses.
5. Tin.
6. Presence of free - moving electrons.
7. A mixture of two or more elements (at least one metal); can have improved properties.
8. Regular and repeating atomic arrangement.
9. Number of protons in an atom's nucleus; indicates element's identity and position in periodic table.
10. Metals.
11. Based on atomic mass and recurring chemical properties.
12. Grouped in columns (groups).
13. Full outer electron shell.