Which electron configuration represents an excited state for an atom for calcium

1. 2-8-7-1

2. 2-8-7-2

3. 2-8-7-3

4. 2-8-8-2

Hydrogen gas is collected over water at 21 degrees Celsius. At 21 degrees Celsius the vapor pressure of water is 18.7 torr. If the barometric pressure is 758 torr, what is the pressure of hydrogen gas?

You are performing an experiment in a lab to attempt a new method of producing pure elements from compounds. The only problem is that you do not know what element will form. By your previous calculations you know that you will have 6.

Why is it necessary to wait 10 minutes before adding iki solution to the test tubes?

Explain how antimony is useful for humans. What is it used for?

Which statement about velocity is true? A. It has only magnitude. B. It has only direction. C. It has magnitude and direction. D. It is a scalar quantity.

What is the mass in grams of 85.32 mL of blood plasma with a density of 1.03 g/mL?

The molar solubility of Ag2CO3 is 0.074M at 10°C. What is the Ksp of Ag2CO3 at the same degree?

You would know you were in the troposphere If? It were raining on you You were floating in space You were flying in a high altitude jet You were in the ozone later

A burning match is an example of a chemical change phase change nuclear change physical change

The table below shows the shapes of two samples, C and D, when placed in three containers of different shapes.