The Atom and The Electron Relearning Activity

Beryllium has how many neutrons?

• 2

• 4

• 5

• 9

Answer explanation

Beryllium has an atomic number of 4, meaning it has 4 protons. The most common isotope of beryllium has a mass number of 9. To find the number of neutrons, subtract the number of protons from the mass number: 9 - 4 = 5.

Tags

NGSS.MS-PS1-1

How many electrons does a neutral atom of carbon have?

• 4

• 12

• 6

• 8

Answer explanation

A neutral atom of carbon has 6 protons and, to maintain neutrality, it must also have 6 electrons. Therefore, the correct answer is 6.

Tags

NGSS.HS-PS1-1

What is an isotope?

• Atoms of the same element with different numbers of protons

• Atoms of different elements with the same number of neutrons

• Atoms of the same element with different numbers of neutrons

• Atoms of the same element with the same number of protons and electrons but different numbers of neutrons

Answer explanation

An isotope refers to atoms of the same element that have the same number of protons but different numbers of neutrons. This results in different atomic masses while retaining the same chemical properties.

What is the role of neutrons in the nucleus?

• To repel protons and provide stability

• To attract electrons into the nucleus

• To add mass to the atom without changing its chemical properties

• To provide electrical charge to the nucleus

Answer explanation

Neutrons add mass to the atom without affecting its chemical properties, as they are neutral particles. This mass contributes to the overall stability of the nucleus, allowing it to hold protons together despite their repulsive forces.

Tags

NGSS.HS-PS1-8

What is the main difference between the mass number and the atomic number of an atom?

• The mass number includes the number of protons and electrons, while the atomic number includes protons and neutrons.

• The mass number includes the number of protons and neutrons, while the atomic number is just the number of protons.

• The atomic number includes the number of protons and electrons, while the mass number includes protons and neutrons.

• There is no difference; they are the same.

Answer explanation

The mass number is the total of protons and neutrons in an atom's nucleus, while the atomic number is solely the number of protons. This distinction is crucial for understanding atomic structure.

What is the significance of the atomic nucleus in terms of mass?

• It contains all the atom's mass.

• It contains a negligible amount of the atom's mass.

• It contains over 99% of the atom's mass.

• It contains exactly half of the atom's mass.

Answer explanation

The atomic nucleus contains protons and neutrons, which are much more massive than electrons. Therefore, it accounts for over 99% of the atom's mass, making this choice the correct answer.

Tags

NGSS.HS-PS1-8

Match the following

• # protons & the identity of the element

• mass number

• no charge and mass of 1 amu

• atomic number

• negative charge and almost no mass

• electron

• positive charge and mass of 1 amu

• neutron

• sum of the mass of neutrons and protons

• proton

What is the electron configuration of a neutral oxygen atom?

• 1s² 2s² 2p³

• 1s² 2s² 2p⁴

• 1s² 2s² 2p⁶

• 1s² 2s² 2p⁵

Answer explanation

A neutral oxygen atom has 8 electrons. The electron configuration is 1s² 2s² 2p⁴, indicating 2 electrons in the first shell and 6 in the second shell, with 4 in the 2p subshell. Thus, the correct choice is 1s² 2s² 2p⁴.

Tags

NGSS.HS-PS1-1

Which of the following elements has the electron configuration [Ne] 3s² 3p⁴?

• Phosphorus

• Chlorine

• Argon

• Sulfur

Answer explanation

The electron configuration [Ne] 3s² 3p⁴ corresponds to sulfur (S), which has 16 electrons. Phosphorus has 15 electrons, chlorine has 17, and argon has 18, making sulfur the correct choice.

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

What is the maximum number of electrons that can occupy the 3d subshell?

• 2

• 6

• 10

• 14

Answer explanation

The 3d subshell can hold a maximum of 10 electrons. This is because it has 5 orbitals, and each orbital can hold 2 electrons, resulting in 5 x 2 = 10 electrons.