if an atom has 4 protons, 5 neutrons, and 4 electrons, what is the mass number of this atom? How do you know?

How much time does it take for light from the center of the galaxy to reach Earth?

Do all substances have the same chemical formula? why or why not?

Which outer planet has a characteristic storm called the Great Red Spot?

The electronegativity is 2.1 for H and 3.0 for N. Based on these electronegativities, NH4 would be expected to The electronegativity is 2.1 for H and 3.0 for N.

What is the type of stimulus is an allergen such as pollen A.) response to a stimulus B.) external stimulus C.) internal stimulus D.) inborn stimulus

What is the electron configuration of a sulfur atom in the ground state?

Unsaturated fatty acids are often classified according to the number of carbon atoms between the terminal methyl carbon (the omega carbon) and the closest double bond to the methyl end of the chain.

Suppose the average concentration of copper in water is measured to be 2.5 x 10" M. a. Express this concentration in mg/L. b. Express this concentration in ug/L. c.

If I add water to oil what will happen

Commercial fertilizers, which are made by humans, are used to enrich soil for healthier crops. However, erosion may carry the fertilizer chemicals to the oceans. The presence of these chemicals may cause certain kinds of algae to reproduce rapidly.