What determines the mass number of an element?

the number of protons minus the number of electrons

the number of protons

the total number of protons, electrons, and neutrons

the total number of neutrons and protons

H2 + N2 - - - > NH3 For this unbalanced chemical equation, what is the coefficient for hydrogen when the equation is balanced? A. 1 B. 2 C. 3 D. 4

Which of the following statements is true? A. Isotopes have the same physical properties as the normal atom but different chemical properties. B. Isotopes have the same chemical properties as the normal atom but different physical properties. C.

A physical change differs from a chemical change in hat waste products are formed through chemical changes. true or false?

What are polymers? Long chains of carbon molecules Small groups of halogen molecules Long chains of halogen molecules Small groups of carbon molecules

How much heat is absorbed/released when 20.00 g of NH3 (g) (17.0307g/mol) react in the presence of excess O2 (g) to produce NO (g) and H2O (l) according to the following chemical equation? 4 NH3 (g) + 5 O2 (g) → 4 NO (g) + 6 H2O (l) ΔH° = 1168 kJ

Which atom has a change in oxidation number of - 3 in the following redox reaction K2Cr2O7 + H2O + S - - > KOH + Cr2O3 + SO2

Why does fluorine have a higher electronegativity than lithium?

What mineral is this? Irregularly shaped, white with nonmetallic luster, the hardness of 2.5, shows cubic cleavage and dissolves easily in water.

The passage of the USA Patriot Act of 2001 and the creation of the Department of Homeland Security reflect the determination of the United States government to (1) search for weapons of mass destruction in South Asia (2) increase the globalization

Is it possible for 2 different elements to have the same atomic number