January 23, 2020

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...

January 22, 2020

Lewis Dot structure is a representation of how electrons are arranged in a molecule.

To correctly draw lewis dot structures we need to follow the following six steps.

1. Calculate the total number of valence electrons

2. Connect atoms in a molecule using bonds

3. Subtract electrons used in bonds from the total electrons calculated in part 1

4. Use remaining electrons to make outer atoms happy (octet, 8 electrons) but rem...

January 21, 2020

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


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...

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