When an atom transitions from an excited state to the ground state, it

• absorbs energy.

• releases energy.

• remains at the same energy level.

• gains chemical energy.

Answer explanation

When an atom transitions from an excited state to the ground state, it releases energy in the form of photons. This process is fundamental in quantum mechanics and is how atoms return to their stable state.

Tags

NGSS.HS-PS4-3

What does the magnetic quantum number describe?

• the orientation of the orbital in space.

• the energy level of the electron.

• the spin of the electron.

• the type of chemical bond formed.

Answer explanation

The magnetic quantum number indicates the orientation of an orbital in space, which is crucial for understanding how electrons are arranged around the nucleus. It does not describe energy levels, spin, or chemical bonds.

What does the magnetic quantum number indicate?

• the energy level of the electron.

• the orientation of the orbital in space.

• the type of element in the periodic table.

• the size of the electron cloud.

Answer explanation

The magnetic quantum number specifies the orientation of an orbital in space, indicating how the orbital is aligned relative to the other orbitals. It does not determine energy level, element type, or size of the electron cloud.

Which quantum number determines the size of an electron's orbit in an atom?

• magnetic quantum number.

• orbital quantum number.

• spin quantum number.

• principal quantum number.

Answer explanation

The principal quantum number determines the size of an electron's orbit in an atom, indicating the energy level and distance from the nucleus. Higher values correspond to larger orbits.

Which of the following shapes best represents the d orbitals of a transition metal atom?

• a sphere.

• a cloverleaf.

• a cube.

• a pyramid.

Answer explanation

The d orbitals of transition metals are characterized by their cloverleaf shape, which consists of four lobes. This distinguishes them from s (spherical), p (dumbbell), and other shapes, making 'a cloverleaf' the correct choice.

What is the number of possible orientations for a "p" orbital around the nucleus?

• 1

• 2

• 3

• 4

Answer explanation

A 'p' orbital has three possible orientations in space, corresponding to the three axes (x, y, z). Therefore, the correct answer is 3.

What is the electron configuration of phosphorus using noble gas notation?

• [Ne] 3s²3p³

• [Ar] 3s²3p³

• [He] 2s²2p⁶3s²3p³

• [Ne] 3s²3p²

Answer explanation

Phosphorus has an atomic number of 15. Using noble gas notation, we start with the nearest noble gas, neon ([Ne]), and add the remaining electrons: 3s²3p³, which accounts for all 15 electrons.

Tags

NGSS.HS-PS1-1

Which of the following choices best represents the noble gas configuration of iron?

• [He] 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁶

• [Mg] 3p⁶ 4s² 3d⁶

• [Ar] 4s² 3d⁶

• [Ca] 3d⁶

Answer explanation

The noble gas configuration of iron (atomic number 26) is best represented by [Ar] 4s² 3d⁶, indicating it has the electron configuration of argon plus two electrons in the 4s subshell and six in the 3d subshell.

Tags

NGSS.HS-PS1-1

The ground state electron configuration of sulfur is

• 1s² 2s² 2p⁶ 3s² 3p⁴

• 1s² 2s² 2p⁴ 3s² 3p⁴

• 1s² 2s² 3s² 3p⁴

Answer explanation

The ground state electron configuration of sulfur (atomic number 16) is 1s² 2s² 2p⁶ 3s² 3p⁴, which accounts for all 16 electrons. The other options do not correctly represent the distribution of electrons.

Tags

NGSS.HS-PS1-1

Which row correctly represents the maximum number of electrons that can be held in the first four atomic orbitals?

• Row 1

• Row 2

• Row 3

• Row 4

Answer explanation

The first four atomic orbitals (1s, 2s, 2p, 3s) can hold a maximum of 2, 2, 6, and 2 electrons respectively, totaling 12 electrons. Row 2 correctly represents this maximum capacity.