Which of the following pairs of elements could possibly be found in the same group on the periodic table? (2 points) a forms a 2+ ion; b is in group 2. a is a noble gas; b forms a 1− ion. a has 3 valence electrons; b is a halogen in group 17. a forms a 2− ion; b is a metal in group 2.

Which statement describes the appearance of a temperature-vs.-time graph? a horizontal line shows that the temperature increases at a constant rate over time. a vertical line shows that the temperature decreases at a constant rate over time. horizontal lines where the temperature is constant during phase changes connect upward-sloping lines where the temperature increases. horizontal lines where the temperature increases are connected by upward-sloping lines where the temperature is constant for each phase.

What is the chemical name of the compound na2co3? use the list of polyatomic ions and the periodic table to you answer. a. sodium carbon oxide b. sodium carbonate c. sodium(ll) carbonate d. sodium oxalate

Air can be considered a mixture. which statement does not explain why?