Electrons and Periodic Trends Review

What is meant by “ground state” and “excited” electrons?

• Ground state is the lowest energy state; excited state is a higher energy state.

• Ground state is a higher energy state; excited state is the lowest energy state.

• Both are the same energy state.

• Ground state is when electrons are removed; excited state is when electrons are added.

Answer explanation

The ground state refers to the lowest energy level of an atom, where electrons are in their most stable configuration. Excited electrons are those that have absorbed energy and moved to a higher energy state.

Why are emission spectrums formed?

• Due to the absorption of energy by electrons.

• Due to the release of energy by electrons as they return to lower energy levels.

• Due to the collision of atoms.

• Due to the splitting of atoms.

Answer explanation

Emission spectrums are formed when electrons release energy as they transition from higher to lower energy levels. This release of energy occurs in the form of light, resulting in distinct spectral lines.

Spectral lines that are in the red color range are located on the (left / right) of the emission graph, and indicate a (rise / drop) in energy levels that are (low / high).

• Left, rise, high

• Right, drop, low

• Left, drop, low

• Right, rise, high

Answer explanation

Spectral lines in the red range are found on the right of the emission graph, indicating a drop in energy levels that are low. This aligns with the correct answer: Right, drop, low.

Match the following terms with their definitions.

• Electrons located in the outermost s and p orbitals that determine chemical properties.

• Free

• Electrons located in the inner shells, not involved in chemical bonding.

• Valence

• Electrons that are not bound to any atom and can move freely.

• Inner

What group on the periodic table have 2 valence electrons?

• Group 1

• Group 2

• Group 3

• Group 4

Answer explanation

Group 2 elements, also known as the alkaline earth metals, have 2 valence electrons. This distinguishes them from Group 1, which has 1 valence electron, and other groups.

Vertical columns in a periodic table are called __________________________ and all share the same number of __________________________ indicating they have similar chemical properties.

• Periods, protons

• Groups, valence electrons

• Rows, neutrons

• Columns, atomic numbers

Answer explanation

Vertical columns in a periodic table are called groups, and elements in the same group have the same number of valence electrons, which gives them similar chemical properties.

Organize from SMALLEST to LARGEST atomic radius: Nitrogen, Aluminum, Strontium

• Strontium, Aluminum, Nitrogen

• Nitrogen, Aluminum, Strontium

• Aluminum, Nitrogen, Strontium

• Strontium, Nitrogen, Aluminum

Answer explanation

Atomic radius increases down a group and decreases across a period. Nitrogen (smallest) is in period 2, Aluminum (larger) in period 3, and Strontium (largest) in period 5. Thus, the order is Nitrogen, Aluminum, Strontium.

Match the following elements with their atomic radius order from SMALLEST to LARGEST.

• Order of elements with decreasing atomic radius

• Oxygen, Sulfur, Selenium

• Order of elements with random atomic radius

• Oxygen, Selenium, Sulfur

• Order of elements with increasing atomic radius

• Selenium, Sulfur, Oxygen

Organize the elements Oxygen, Sulfur, and Selenium from LEAST to MOST electronegative.

• Selenium, Sulfur, Oxygen

• Oxygen, Sulfur, Selenium

• Sulfur, Selenium, Oxygen

• Sulfur, Oxygen, Selenium

Answer explanation

Electronegativity increases across a period and decreases down a group. Oxygen is the most electronegative, followed by Sulfur, and Selenium is the least. Thus, the correct order from least to most electronegative is Selenium, Sulfur, Oxygen.

Organize the elements Oxygen, Sulfur, and Selenium from SMALLEST to LARGEST ionization energy.

• Selenium, Sulfur, Oxygen

• Oxygen, Sulfur, Selenium

• Sulfur, Selenium, Oxygen

• Sulfur, Oxygen, Selenium

Answer explanation

Ionization energy increases across a period and decreases down a group. Oxygen has the highest ionization energy, followed by sulfur, and selenium has the lowest. Thus, the order from smallest to largest is Selenium, Sulfur, Oxygen.