Answer:
1. True
2. True
3. True
4. B. vertical
5. B. periods
6. A, B, C, D
7. C. Atomic
8. B. false
9. A. True
10. A. 112
Explanation:
1. Helium is a natural gas found in the atmosphere and below ground.
2. Neon is also natural gas found in Earth's atmosphere and can be seen on the periodic table.
3. An element is considered a pure substance because it is made up of only one type of atom and cannot be broken down into a simpler form.
4. Families/groups go up and down (vertical), while periods go across (horizontal)
5. As I just mentioned, periods run horizontally on the Periodic table.
6. Matter is everything that takes up space and has mass. Therefore, all of the given answers consist of matter. Why else would they matter? :)
7. The title of the "Most Accurate Clock In The World" goes to the British atomic clock at UK's National Physical Laboratory (NPL).
8. Almost 99% of the mass of the human body is made up of six elements: oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus. Only about 0.85% is composed of another five elements: potassium, sulfur, sodium, chlorine, and magnesium. Therefore, we consist of more that 99%.
9. A grain of sand is relatively small; about the size of one atom.
10. The periodic table has 112 elements because there were 112 elements before IUPAC reviewed elements 113, 115, 117 and 118, and decided to give them official names and symbols. This was relatively recent. The total number of elements is 118 though.
I would like to apologize in advance if any of these were incorrect.
