The symbol of the element in Period 4 and Group 7A(17) is ________.

An s orbital can hold ________ electrons.

A 70-year-old woman comes to the office for the first time in several years because she has recently begun to feel anxious. She describes nervousness and vague somatic symptoms and she worries about the nature of these symptoms. The symptoms wax and wane throughout the day and are bothersome. She reports no problems with memory or other cognitive functions and she is not depressed. Which one of the following is most likely to be excluded from the differential diagnosis?

Pentane (C5H12) reacts with oxygen (O2) to form carbon dioxide (CO2) and water (H2O) according to the following reaction. Answer the following question(s) about this reaction. C5H12(l) + ? O2(g) → ? CO2(g) + ? H2O(g)What is the coefficient for oxygen in the balanced equation?

Sulfur is more metallic than ________.

Sn has 68 neutrons.

Identify the physical change in the following list.

Calcium has ________ valence electron(s).

Sulfur atoms are larger than than ________ atoms.

Which of the following would NOT be a physical change?