What is the number after an elements name, representing the sum of its protons and neutrons

The kind of hazardous waste disposal that most clearly resemble recycling is

How do the properties of elements in the same row of the periodic table compare?

The K w for water at 0 ∘ C is 0.12 * 10 - 14. Calculate the pH of a neutral aqueous solution at 0 ∘ C.

Which group of elements will readily lose one electron to meet the octet rule? Alkaline Earth Metals c. Halogens Alkali Metals d. Both A and B

The thermal decomposition of dimethyl ether (C H 3) 2 O (g) → C H 4 (g) H 2 (g) CO (g) is to be carried out in an isothermal 2.00-liter laboratory reactor at 600°C. The reactor is charged with pure dimethyl ether at a pressure of 350 torr.

Since the early 2000s, careers in the field of genetics have grown at a rapid pace. Which of these is a probable cause for this explosion of available and expanding jobs?

How many litres of 0.215 m NaCl contains 4.30 mol of this salt? Assume this solvent is H2O I'm confused on this question because little m is molality but when I looked this up on google, someone solved the problem assuming it was molarity

How can a neutral atom become a positively-charged particle?

The last column of the periodic table contains the noble gases, elements that do not easily form chemical bonds.

When pollution is removed from the air by a natural process, it