Question

in chemistry, a formula is used to represent
a all of these
b an element
c a metal
d none of these
e a compound
question 5 (1 point)
which of the following statements are true?
i. the number of protons in an element is the same for all neutral a
ii. the number of electrons in an element is the same for all neutral
iii. the number of neutrons in an element is the same for all neutra
o a i, ii, and iii are all true
o b only i and iii are true.
o c i, ii, and iii are all false
o d only i and ii are true.
o e only ii and iii are true

Explanation:

First Question (Chemistry Formula Representation)

In chemistry, a chemical formula can represent an element (e.g., \( \text{O} \) for oxygen), a compound (e.g., \( \text{H}_2\text{O} \) for water), and metals (which are elements, e.g., \( \text{Fe} \) for iron). So a formula can represent an element, a metal, a compound—thus "all of these" is correct.

• Statement I: The number of protons (atomic number) is unique and constant for all neutral atoms of an element. True.
• Statement II: In neutral atoms, electrons equal protons (to balance charge), so for neutral atoms of an element, electron count is constant. True.
• Statement III: Isotopes of an element have different neutron counts (e.g., carbon - 12 and carbon - 14). So neutron count is not the same for all neutral atoms of an element. False.

Thus, only I and II are true.

Answer:

a. all of these

Second Question (Protons, Electrons, Neutrons in Elements)