Unit 2: Electron config & emission spectra

What occurs when electrons fall from a higher energy level to a lower energy level in an atom?

• The atom absorbs light

• The atom emits light

• The atom turns into a neutron

• The atom loses electrons

Answer explanation

When electrons jump to a higher energy level, the atom absorbs light. This energy is needed to move the electrons to a higher state, rather than emitting light, which occurs when they fall back to a lower energy level.

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NGSS.HS-PS4-3

How does the knowledge of electron behavior help shape the periodic table?

• It determines the atomic mass

• It reveals patterns in chemical properties

• It changes the number of protons

• It affects the color of elements

Answer explanation

Understanding electron behavior helps identify trends in how elements interact chemically, leading to the organization of the periodic table by similar properties. This reveals patterns in chemical properties, making it the correct choice.

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NGSS.HS-PS1-1

NGSS.HS-PS1-2

Which sublevels are present in the breakdown of energy levels according to the diagram?

• s, p, d, f

• a, b, c, d

• x, y, z, w

• 1, 2, 3, 4

Answer explanation

The correct answer is 's, p, d, f' as these are the sublevels present in the breakdown of energy levels in atomic structure, representing different shapes of electron orbitals.

How many orbitals are present in the 'd' sublevel?

• 1

• 3

• 5

• 7

Answer explanation

The 'd' sublevel contains 5 orbitals, which are designated as dxy, dyz, dzx, dx2-y2, and dz2. Each orbital can hold a maximum of 2 electrons, making the total capacity of the 'd' sublevel 10 electrons.

What letter is used to symbolize energy levels in an atom?

• m

• n

• l

• e

Answer explanation

The letter 'n' is used to symbolize energy levels in an atom, known as principal quantum numbers. It indicates the size and energy of the orbital, with higher 'n' values corresponding to higher energy levels.

If each p orbital holds 2 electrons and there are 3 p orbitals, what is the maximum number of electrons that can be held in the p sublevel?

• 2

• 3

• 4

• 6

Answer explanation

Each p orbital can hold 2 electrons, and there are 3 p orbitals (2 electrons/orbital x 3 orbitals = 6 electrons). Therefore, the maximum number of electrons that can be held in the p sublevel is 6.

What is the correct electron configuration for lithium (Li) with atomic number 3?

• 1s² 2s¹

• 1s² 2p¹

• 1s¹ 2s²

• 1s² 2s²

Answer explanation

Lithium (Li) has an atomic number of 3, meaning it has 3 electrons. The correct electron configuration is 1s² 2s¹, indicating 2 electrons in the 1s subshell and 1 electron in the 2s subshell.

Tags

NGSS.HS-PS1-1

How are electron spins represented in orbital diagrams?

• By different colors

• By numbers

• By arrows pointing in opposite directions

• By circles and squares

Answer explanation

In orbital diagrams, electron spins are represented by arrows pointing in opposite directions. This notation indicates the two possible spin states of an electron, which are often referred to as 'spin up' and 'spin down'.

Which of the following best describes the process of filling electrons in orbitals?

• All electrons fill one orbital before moving to the next

• Electrons fill each orbital singly with parallel spins before pairing up

• Electrons are randomly distributed among orbitals

• Electrons fill the highest energy orbital first

Answer explanation

The correct choice states that electrons fill each orbital singly with parallel spins before pairing up, following Hund's rule. This ensures maximum stability and minimizes electron-electron repulsion in orbitals.

Which part of the electromagnetic spectrum has the highest energy?

• Gamma rays

• Infrared

• Radio waves

• Visible light

Answer explanation

Gamma rays have the highest energy in the electromagnetic spectrum due to their short wavelength and high frequency, surpassing infrared, radio waves, and visible light.

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NGSS.HS-PS4-4