Which electron shell in an atom of calcium in the ground state has an electron with the greatest amount of energy?

(1) 1

(2) 2

(3) 3  

(4) 4

Answer: 4

Explanation: The further an electron is from the nucleus, the higher it's energy is. Therefore, electrons in the valence shell (outermost shell) have the highest amount of energy. If we look at the Reference Table: Periodic Table of Elements section, we can find calcium...

The only two elements in alkenes and alkynes are

(1) carbon and nitrogen

(2) carbon and hydrogen

(3) oxygen and nitrogen

(4) oxygen and hydrogen

Answer: (2) carbon and hydrogen

Explanation:

If we look at the Chemistry Regent Reference table, we will see on Table Q, that alkenes and alkynes belong to the Homologous Series of Hydrocarbons. Hydrocarbons are organic molecules that contain carbon and hydrogen. Therefore, they mu...

Intermolecular forces are forces of attraction between molecules. These forces influence properties of substances such as boiling and melting points, phases at room temperature, viscosity and many more.

Intermolecular forces can be divided into 4 major categories:

1. ION-ION

This is the strongest intermolecular force. It is present in all ionic compounds. To recognize it, look at the formula and see if it has metal with a...

Which of the following substrates would react most efficiently in a substitution reaction with sodium cyanide (NaCN)?

(A) 1-iodohexane
(B) 1-fluorohexane
(C) (R)-2-bromohexane
(D) chlorocyclohexane
(E) 1-bromo-1-methylcyclohexane

Answer: (A) 1-iodohexaneA

Solution:

We first must figure out which reaction does the question ask about. The question mentions substitution reaction, thus either SN1 or SN2. We are also given NaCN...

What is the chemical name of the compound NH4SCN?

(1) ammonium thiocyanate

(2) ammonium cyanide
(3) nitrogen hydrogen cyanide

(4) nitrogen hydrogen sulfate

Answer: (1) ammonium thiocyanate

Explanation: In order to name a compound, we must first figure out whether it is ionic or covalent. Ionic compounds can be divided into three categories: metal + nonmetal, meta+ polyatomic ion, polyatomic ion+ polyatomic ion, polyatomic io...

 Which electron configuration represents the electrons in an atom of sulfur in an excited state?

(1) 2 – 8 – 6

(2) 2 – 7 – 7

(3) 2–8– 7

 (4) 2–7– 8

Answer : 2) 2-7-7

Explanation: We must first look at the Periodic Table at the Reference Table, and find Sulfur. Sulfur's electron configuration is 2-8-6 according to the Reference Table. An excited state is a state in which an electron jumps to a higher energy level, while the g...