Unit 2 Post Quiz

Which particle is considered the basic building block of matter in atomic theory?

• Neutron

• Photon

• Atom

• Quark

Answer explanation

The basic building block of matter in atomic theory is the Atom, as it is the smallest unit of an element that retains the properties of that element.

Tags

NGSS.MS-PS1-1

What is a characteristic of isotopes of the same element?

• They have different numbers of protons.

• They have the same number of electrons but different numbers of neutrons.

• They have the same number of neutrons and electrons.

• They have different atomic numbers.

Answer explanation

Isotopes of the same element have the same number of electrons but different numbers of neutrons, leading to variations in atomic mass.

Which subatomic particle determines the chemical properties of an element?

• Proton

• Neutron

• Electron

• Nucleus

Answer explanation

The electron determines the chemical properties of an element by its arrangement in the outer shell, influencing bonding and reactivity.

Explain how the quantum mechanical model of the atom differs from the Bohr model in terms of electron behavior and energy levels.

• The quantum mechanical model describes electrons as particles orbiting the nucleus, while the Bohr model describes them as waves with no definite position.

• The quantum mechanical model and the Bohr model both describe electrons as particles orbiting the nucleus.

• The quantum mechanical model describes electron behavior probabilistically and incorporates discrete energy levels, while the Bohr model does not.

• The Bohr model and the quantum mechanical model are essentially the same.

Answer explanation

The quantum mechanical model describes electron behavior probabilistically and incorporates discrete energy levels, while the Bohr model does not.

Consider two elements, A and B, with atomic numbers 11 and 17, respectively. How do their electron configurations relate to their positions on the periodic table, and what can you infer about their chemical properties?

• Element A has more valence electrons than element B, making it more reactive.

• Element B has more valence electrons than element A, making it more reactive.

• Element A and element B have the same number of valence electrons, making them equally reactive.

• The electron configurations of elements A and B have no relation to their chemical properties.

Answer explanation

Element B has more valence electrons than element A, making it more reactive.

How many valence electrons does an atom of Nitrogen (N) have?

• 2

• 3

• 5

• 7

Answer explanation

An atom of Nitrogen (N) has 5 valence electrons, which can be determined by looking at its position in the periodic table (group 15) and knowing that it has 5 electrons in its outer shell.

Tags

NGSS.HS-PS1-1

Which group of elements in the periodic table typically has 1 valence electron?

• Alkaline Earth Metals

• Halogens

• Noble Gases

• Alkali Metals

Answer explanation

Alkali Metals typically have 1 valence electron, making them the group of elements in the periodic table with this characteristic.

How many valence electrons does a neutral atom of helium have?

• 2

• 4

• 6

• 8

Answer explanation

A neutral atom of helium has 2 valence electrons, as it is located in the second period of the periodic table and belongs to group 18.

What is the name of an ion with a negative charge?

• proton

• anion

• neutron

• cation

Answer explanation

An ion with a negative charge is called an anion. Anions have gained electrons, resulting in a negative charge.

What is the difference between an atom and an ion?

• An atom has different numbers of protons, while an ion has different numbers of electrons.

• An atom has different numbers of electrons, while an ion has different numbers of protons.

• An atom has different numbers of neutrons, while an ion has different numbers of protons.

• An atom has the same number of protons, while an ion has different numbers of electrons.

Answer explanation

An atom has the same number of protons, while an ion has different numbers of electrons.