2. An element's atomic number is the A. number of protons in an atom's nucleus. B. mass of the atom. C. weight of the atom. D. sum of the protons and neutrons in an atom.

What is the name of the compound that has the formula N2O? a. nitrogen oxide b. dinitrogen oxide c. nitrogen dioxide d. dinitrogen monoxide

Otters are one of the few animals that can use tools. When otters need to open the hard shells of the animals they eat, they have been known to use a rock. Some, but not all, otters have been seen using this behavior. This behavior is most likely.

The election configuration has of an element is 1s^2 2s^2 2p^1. How many valence electrons does the element have?

True or false Liquid particles move faster than gas particles

The total amount of energy before and after a chemical reaction is the same. Thus, energy is A. conserved. B. created. C. destroyed. D. the same as mass.

Explain why elements and compounds are pure substances

Which term best describes the water in a sugar-water solution?

What are the forces that create electromagnetism?

The nose is an organ that acts as an airway for oxygen to enter the body. The nose also contains hairs that trap small foreign objects and stop them from entering the body. Which two systems does the nose play a role in? A. respiratory and immune B.

HBr + Mg (OH) 2 MgBr2 + H2O