Which of these ions has the largest radius (S2-, Cl-, K+, or S2-)

Which of the following is the electronic configuration for the Fe2+ ion?

Choose the correct name for NiS2. 

Which of the quantities below are equal in number of atoms present?   3.0 mol sulfur dioxide  9.0 mol helium gas 6.0 mol liquid bromine  

What is the energy of a photon associated with a light of a wavelength of 550 nm?

A sample 3.91 x 1025 atoms of tungsten (W), what would the mass of the sample be in kilograms (kg)?

Which of the following electron transitions would emit energy?   a. n=5 → n=3  b. n= 2 → n=4 c. n=3 → n=6

Which of the following gases have the greatest root mean square velocity/speed?

The reaction of solid silicon (Si) with gaseous oxygen can be used to produce silicon trioxide. How many grams of silicon trioxide are produced in the reaction when 4.25 g of silicon reacts with 3.75 g of oxygen gas?    2Si (s) + 3O2 (g)

If a system releases heat and the volume of the container increases what are the signs of q and w?