Summative Test 1 Review

How can you determine the reactivity of the atom?

• # electrons

• #protons

• # of valence electrons

• # neutrons

Answer explanation

The reactivity of an atom is determined by its number of valence electrons. These are the electrons found in an atom's outermost shell that participate in chemical reactions. Thus, the correct answer is '# of valence electrons'. The number of protons, neutrons or total electrons does not directly affect an atom's reactivity.

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

What subatomic particle determines an atom's identity?

• Electrons

• Neutrons

• Protons

Answer explanation

The identity of an atom is determined by the number of protons it contains. Everything else in an atom can change without changing what element it is. Therefore, the correct answer to the question is 'Protons'. Despite Electrons and Neutrons being subatomic particles, they do not determine an atom's identity.

Which statement describes a proton?

• positive, 1 amu

• negative, 1/2000 amu

• no charge

• 1 amu positive, 1/2000 amu

Answer explanation

The question asks about the characteristics of a proton. The correct answer is 'positive, 1 amu', which indicates that a proton is positively charged and has a mass of 1 atomic mass unit. Other options were incorrect because they either had the wrong charge, wrong mass, or both.

Which two elements will act the most similar chemically?

• Ca / K

• C / Br

• Mn / Tc

• Cs / Au

Answer explanation

The most chemically similar elements are usually those that belong to the same group in the periodic table as they have the same number of electrons in their outermost shell. Carbon (C) and Bromine (Br) belong to different groups, hence they don't act similar chemically. Therefore, the other options are incorrect.

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

What group is made of metals that react violently with water?

• Group 18: Noble Gases

• Group 17: Halogens

• Group 2: Alkaline-Earth Metals

• Group 1: Alkali Metals

Answer explanation

The question is about a group of metals that react violently with water. The correct answer is Alkali Metals, which are in Group 1. Alkali Metals, due to their single electron in their outermost shell, are highly reactive, especially with water, even at room temperature. This property is not observed in other groups like Noble Gases, Halogens, or Alkaline-Earth Metals.

What is a valence electron?

• Outer shell electron that determines period of an atom

• Outer shell electron that determines reactivity

• electrons on the first energy level

• electrons inside the nucleus

Answer explanation

A valence electron is an electron in the outer shell of an atom. These electrons play a key role in determining the reactivity of an atom. However, the answer refers to valence electrons as those determining the period of an atom, which is not generally accepted. While valence electrons affect an atom's chemical properties, they do not directly set the atom's period in the periodic table.

What is the most stable group on the periodic table?

• Transition Metals

• G17: Halogens

• G18: Noble Gasses

• Alkali Metals

Answer explanation

The most stable group on the periodic table is indeed the Noble Gasses. This is because they have a full set of electrons in their outermost shell, making them inert and highly stable. This stability separates them from other groups like Transition Metals, Halogens, and Alkali Metals, which don't have full electron shells and are therefore more reactive and less stable.

How many valence electrons does carbon have? __________ How do you know? Explain

• 14

• 4A

• 4

• 6

Where are the metals on the periodic table?

• Along the dark zig-zag line

• To the right

• To the left and bottom

Answer explanation

The metals on the periodic table are found on the left and bottom. This includes both the transition metals and lanthanide and actinide series. The options to the right or along the dark zig-zag line are incorrect as they correspond to non-metals and metalloids respectively.

Which element is most stable?

• Argon

• Phosphorus

• Oxygen

• Lithium

Answer explanation

Argon is the most stable element among the given options. It is a noble gas, which means it has a full valence electron shell. This makes it extremely stable and unreactive compared to Phosphorus, Oxygen, and Lithium.