Question

1. which of these is an example of a molecule?

a. oxygen-o₂ b. salt-nacl c. water-h₂o d. both a and c

1. what is the symbol for oxygen?

a. o b. ox c. oy d. om

1. it is considered as an element.

a. carbon b. carbon dioxide c. carbon monoxide d. carbohydrates

1. the periodic table shows all ______ elements.

a. 108 b. 118 c. 128 d. 138

1. which of the following is a mixture, not a compound?

a. air b. water c. salt d. sugar

1. what happens when elements chemically combine?

a. they form a mixture
b. they form a compound
c. they separate
d. they melt
part 2: identification.
write a if it is an atom, m for molecule, element for elements, and c for compounds.
_______1. silver (ag)
_______2. several particles of hydrogen
_______3. carbon dioxide (co2)
_______4. single particle of oxygen
_______5. helium (he)

Explanation:

1. Silver (Ag) is an element as it is a pure substance with only one type of atom.
2. Several particles of Hydrogen form a molecule (H₂).
3. Carbon Dioxide (CO₂) is a compound as it is made of two different elements chemically combined.
4. A single particle of Oxygen is an atom (O).
5. Helium (He) is an element as it is a pure substance with only one type of atom.

Answer:

1. Element
2. M
3. C
4. A
5. Element