Question

which is larger: a sodium atom or an argon atom? a. a sodium atom b. an argon atom c. same atomic size d. there is no way to tell without memorizing the periodic table. question 9 which is larger: a helium atom or a sulfur atom? a. a helium atom b. a sulfur atom c. same atomic size d. there is no way to tell without memorizing the periodic table. question 10 what is the type of ion that has at least one extra electron? a. neutral b. positive ion c. negative ion d. not enough information given.

Explanation:

1. For the comparison of sodium and argon atoms: Sodium (Na) and argon (Ar) are in the same period (3rd period) of the periodic table. Atomic size decreases across a period from left - to - right due to an increase in the effective nuclear charge. Sodium is on the left side and argon is on the right side of the 3rd period, so sodium has a larger atomic radius.
2. For the comparison of helium and sulfur atoms: Helium (He) is in the 1st period and sulfur (S) is in the 3rd period. Atomic size generally increases down a group and across periods from top - to - bottom. Sulfur has more electron shells than helium, so sulfur is larger.
3. For the type of ion with an extra electron: An ion with an extra electron has a negative charge because electrons are negatively charged. A negative ion is called an anion.

Answer:

1. Question 7: A. A sodium atom
2. Question 9: B. A sulfur atom
3. Question 10: C. Negative ion