💡 8th Grade Physical Science: The Periodic Table of Elements Practice Questions
1
Solved Example
Easy Level
💡 The Periodic Table organizes elements based on their properties. Each element has a unique atomic number.
Which element has an atomic number of 6?
Oxygen (O)
Carbon (C)
Nitrogen (N)
Boron (B)
Solution & Explanation
To solve this, we need to recall that the atomic number represents the number of protons in an atom's nucleus and uniquely identifies an element.
Step 1: Locate the element with atomic number 6 on the Periodic Table.
Step 2: You will find that the element with atomic number 6 is Carbon (C).
✅ Therefore, the correct answer is Carbon (C).
2
Solved Example
Medium Level
📌 Elements are broadly classified into metals, nonmetals, and metalloids. These classifications help us understand their general properties.
Based on its position in the Periodic Table, classify the element Sulfur (S), which has an atomic number of 16.
Metal
Nonmetal
Metalloid
Noble Gas
Solution & Explanation
To classify Sulfur, we need to know its position on the Periodic Table relative to the "stair-step" line that separates metals from nonmetals.
Step 1: Locate Sulfur (S) on the Periodic Table. It is in Group 16, Period 3.
Step 2: Observe its position. Sulfur is located to the right of the stair-step line, which generally separates metals (to the left) from nonmetals (to the right).
Step 3: Elements to the far right (excluding the noble gases) are typically nonmetals.
✅ Sulfur is a nonmetal because it is located on the right side of the Periodic Table.
3
Solved Example
Medium Level
💡 Elements in the same group (or family) on the Periodic Table often exhibit similar chemical properties. For example, Lithium (Li), Sodium (Na), and Potassium (K) are all highly reactive metals.
Explain why elements like Lithium, Sodium, and Potassium, which are in Group 1, have similar chemical behaviors.
Solution & Explanation
The chemical behavior of an element is primarily determined by the number of electrons in its outermost shell, often called valence electrons.
Step 1: Understand the organization of groups. Elements in the same vertical column (group) share similar characteristics.
Step 2: Recall that for main group elements, the group number often indicates the number of valence electrons. Group 1 elements (Alkali Metals) all have 1 valence electron.
Step 3: Explain the impact of valence electrons. Having the same number of valence electrons means they will tend to gain, lose, or share electrons in similar ways when forming chemical bonds. For Group 1 elements, they all tend to lose that single valence electron to achieve a stable electron configuration.
✅ Elements in the same group, like Lithium, Sodium, and Potassium, have similar chemical properties because they all have the same number of valence electrons (outermost electrons). This similarity in their electron structure dictates how they will react with other elements.
4
Solved Example
Real World Example
👉 You've probably seen a bright, colorful sign that glows at night. These are often called "neon signs," but they can contain other elements too!
Which group of elements, known for their non-reactivity and use in lighting (like neon signs) and balloons, are found in the far-right column of the Periodic Table?
Alkali Metals
Halogens
Noble Gases
Alkaline Earth Metals
Solution & Explanation
This question asks about a specific group of elements known for being unreactive and having practical applications in everyday items.
Step 1: Consider the properties described: non-reactivity and use in lighting/balloons.
Step 2: Recall the major groups of the Periodic Table.
Step 3: The group in the far-right column (Group 18) consists of elements like Helium, Neon, Argon, Krypton, and Xenon. These elements are known as Noble Gases.
Step 4: Noble gases are famous for their stability and inertness (non-reactivity), making them safe for use in signs and balloons (like helium).
✅ The group of elements known for their non-reactivity and use in lighting and balloons are the Noble Gases.
5
Solved Example
Easy Level
💡 The Periodic Table is arranged in periods (horizontal rows) and groups (vertical columns). The period number tells us about the number of electron shells an atom has.
How many elements are there in Period 1 of the Periodic Table?
1
2
8
18
Solution & Explanation
To determine the number of elements in Period 1, we simply need to look at the first row of the Periodic Table.
Step 1: Locate Period 1, which is the very first horizontal row at the top of the Periodic Table.
Step 2: Identify the elements present in this row. You will find Hydrogen (H) on the far left and Helium (He) on the far right.
Step 3: Count these elements. There are two elements.
✅ There are 2 elements in Period 1 of the Periodic Table.
6
Solved Example
Medium Level
📌 The atomic mass of an element is approximately the sum of its protons and neutrons. The atomic number is the number of protons.
An atom of an element has an atomic number of 17 and an atomic mass of 35. What is the number of neutrons in a typical atom of this element?
17
18
35
52
Solution & Explanation
We can calculate the number of neutrons using the atomic number and atomic mass.
Step 1: Recall the definitions:
Atomic Number (Z) = Number of Protons
Atomic Mass (A) ≈ Number of Protons + Number of Neutrons
Step 2: Identify the given values:
Atomic Number = 17 (so, 17 protons)
Atomic Mass = 35
Step 3: Use the formula to find the number of neutrons:
\[ \text{Number of Neutrons} = \text{Atomic Mass} - \text{Atomic Number} \]
\[ \text{Number of Neutrons} = 35 - 17 \]
\[ \text{Number of Neutrons} = 18 \]
✅ The number of neutrons in a typical atom of this element is 18.
7
Solved Example
Medium Level
💡 Imagine you discover a new element. You find that it is a soft, silvery-white metal that reacts violently with water, producing hydrogen gas and a strong base. It has 19 protons.
Based on this information and your knowledge of the Periodic Table, to which group would this new element most likely belong?
Group 2 (Alkaline Earth Metals)
Group 11 (Coinage Metals)
Group 1 (Alkali Metals)
Group 17 (Halogens)
Solution & Explanation
The description provides key clues about the element's reactivity and properties, which are characteristic of specific groups.
Step 1: Analyze the given properties: "soft, silvery-white metal," "reacts violently with water," "produces hydrogen gas and a strong base." These are hallmark characteristics of the Alkali Metals.
Step 2: Consider the number of protons. An element with 19 protons is Potassium (K).
Step 3: Locate Potassium (K) on the Periodic Table. It is found in Group 1.
Step 4: Confirm that Group 1 (Alkali Metals) elements like Potassium, Sodium, and Lithium are known for their extreme reactivity with water, forming hydrogen gas and strong bases.
✅ This new element would most likely belong to Group 1 (Alkali Metals) due to its highly reactive metallic properties, particularly its violent reaction with water.
8
Solved Example
Real World Example
👉 Copper (Cu) is a widely used element in our daily lives. Think about what it's used for in homes and industries.
What is a primary reason Copper (Cu) is extensively used for electrical wiring in homes and electronic devices?
It is a nonmetal and does not conduct electricity.
It is a good thermal insulator.
It is a metal and an excellent conductor of electricity.
It is a noble gas and is very unreactive.
Solution & Explanation
This question connects the properties of an element to its real-world application.
Step 1: Identify Copper (Cu) on the Periodic Table. It is a transition metal, located in Group 11, Period 4.
Step 2: Recall the general properties of metals. Metals are typically good conductors of heat and electricity, are malleable, and ductile.
Step 3: Consider the options in the context of electrical wiring. Electrical wiring requires materials that can efficiently carry an electric current.
Step 4: Option 3 states that Copper is a metal and an excellent conductor of electricity, which aligns perfectly with its use in wiring.
✅ Copper is primarily used for electrical wiring because it is a metal and an excellent conductor of electricity, allowing it to efficiently transmit electrical current.
8th Grade Physical Science: The Periodic Table of Elements Practice Questions
Example 1:
💡 The Periodic Table organizes elements based on their properties. Each element has a unique atomic number.
Which element has an atomic number of 6?
Oxygen (O)
Carbon (C)
Nitrogen (N)
Boron (B)
Solution:
To solve this, we need to recall that the atomic number represents the number of protons in an atom's nucleus and uniquely identifies an element.
Step 1: Locate the element with atomic number 6 on the Periodic Table.
Step 2: You will find that the element with atomic number 6 is Carbon (C).
✅ Therefore, the correct answer is Carbon (C).
Example 2:
📌 Elements are broadly classified into metals, nonmetals, and metalloids. These classifications help us understand their general properties.
Based on its position in the Periodic Table, classify the element Sulfur (S), which has an atomic number of 16.
Metal
Nonmetal
Metalloid
Noble Gas
Solution:
To classify Sulfur, we need to know its position on the Periodic Table relative to the "stair-step" line that separates metals from nonmetals.
Step 1: Locate Sulfur (S) on the Periodic Table. It is in Group 16, Period 3.
Step 2: Observe its position. Sulfur is located to the right of the stair-step line, which generally separates metals (to the left) from nonmetals (to the right).
Step 3: Elements to the far right (excluding the noble gases) are typically nonmetals.
✅ Sulfur is a nonmetal because it is located on the right side of the Periodic Table.
Example 3:
💡 Elements in the same group (or family) on the Periodic Table often exhibit similar chemical properties. For example, Lithium (Li), Sodium (Na), and Potassium (K) are all highly reactive metals.
Explain why elements like Lithium, Sodium, and Potassium, which are in Group 1, have similar chemical behaviors.
Solution:
The chemical behavior of an element is primarily determined by the number of electrons in its outermost shell, often called valence electrons.
Step 1: Understand the organization of groups. Elements in the same vertical column (group) share similar characteristics.
Step 2: Recall that for main group elements, the group number often indicates the number of valence electrons. Group 1 elements (Alkali Metals) all have 1 valence electron.
Step 3: Explain the impact of valence electrons. Having the same number of valence electrons means they will tend to gain, lose, or share electrons in similar ways when forming chemical bonds. For Group 1 elements, they all tend to lose that single valence electron to achieve a stable electron configuration.
✅ Elements in the same group, like Lithium, Sodium, and Potassium, have similar chemical properties because they all have the same number of valence electrons (outermost electrons). This similarity in their electron structure dictates how they will react with other elements.
Example 4:
👉 You've probably seen a bright, colorful sign that glows at night. These are often called "neon signs," but they can contain other elements too!
Which group of elements, known for their non-reactivity and use in lighting (like neon signs) and balloons, are found in the far-right column of the Periodic Table?
Alkali Metals
Halogens
Noble Gases
Alkaline Earth Metals
Solution:
This question asks about a specific group of elements known for being unreactive and having practical applications in everyday items.
Step 1: Consider the properties described: non-reactivity and use in lighting/balloons.
Step 2: Recall the major groups of the Periodic Table.
Step 3: The group in the far-right column (Group 18) consists of elements like Helium, Neon, Argon, Krypton, and Xenon. These elements are known as Noble Gases.
Step 4: Noble gases are famous for their stability and inertness (non-reactivity), making them safe for use in signs and balloons (like helium).
✅ The group of elements known for their non-reactivity and use in lighting and balloons are the Noble Gases.
Example 5:
💡 The Periodic Table is arranged in periods (horizontal rows) and groups (vertical columns). The period number tells us about the number of electron shells an atom has.
How many elements are there in Period 1 of the Periodic Table?
1
2
8
18
Solution:
To determine the number of elements in Period 1, we simply need to look at the first row of the Periodic Table.
Step 1: Locate Period 1, which is the very first horizontal row at the top of the Periodic Table.
Step 2: Identify the elements present in this row. You will find Hydrogen (H) on the far left and Helium (He) on the far right.
Step 3: Count these elements. There are two elements.
✅ There are 2 elements in Period 1 of the Periodic Table.
Example 6:
📌 The atomic mass of an element is approximately the sum of its protons and neutrons. The atomic number is the number of protons.
An atom of an element has an atomic number of 17 and an atomic mass of 35. What is the number of neutrons in a typical atom of this element?
17
18
35
52
Solution:
We can calculate the number of neutrons using the atomic number and atomic mass.
Step 1: Recall the definitions:
Atomic Number (Z) = Number of Protons
Atomic Mass (A) ≈ Number of Protons + Number of Neutrons
Step 2: Identify the given values:
Atomic Number = 17 (so, 17 protons)
Atomic Mass = 35
Step 3: Use the formula to find the number of neutrons:
\[ \text{Number of Neutrons} = \text{Atomic Mass} - \text{Atomic Number} \]
\[ \text{Number of Neutrons} = 35 - 17 \]
\[ \text{Number of Neutrons} = 18 \]
✅ The number of neutrons in a typical atom of this element is 18.
Example 7:
💡 Imagine you discover a new element. You find that it is a soft, silvery-white metal that reacts violently with water, producing hydrogen gas and a strong base. It has 19 protons.
Based on this information and your knowledge of the Periodic Table, to which group would this new element most likely belong?
Group 2 (Alkaline Earth Metals)
Group 11 (Coinage Metals)
Group 1 (Alkali Metals)
Group 17 (Halogens)
Solution:
The description provides key clues about the element's reactivity and properties, which are characteristic of specific groups.
Step 1: Analyze the given properties: "soft, silvery-white metal," "reacts violently with water," "produces hydrogen gas and a strong base." These are hallmark characteristics of the Alkali Metals.
Step 2: Consider the number of protons. An element with 19 protons is Potassium (K).
Step 3: Locate Potassium (K) on the Periodic Table. It is found in Group 1.
Step 4: Confirm that Group 1 (Alkali Metals) elements like Potassium, Sodium, and Lithium are known for their extreme reactivity with water, forming hydrogen gas and strong bases.
✅ This new element would most likely belong to Group 1 (Alkali Metals) due to its highly reactive metallic properties, particularly its violent reaction with water.
Example 8:
👉 Copper (Cu) is a widely used element in our daily lives. Think about what it's used for in homes and industries.
What is a primary reason Copper (Cu) is extensively used for electrical wiring in homes and electronic devices?
It is a nonmetal and does not conduct electricity.
It is a good thermal insulator.
It is a metal and an excellent conductor of electricity.
It is a noble gas and is very unreactive.
Solution:
This question connects the properties of an element to its real-world application.
Step 1: Identify Copper (Cu) on the Periodic Table. It is a transition metal, located in Group 11, Period 4.
Step 2: Recall the general properties of metals. Metals are typically good conductors of heat and electricity, are malleable, and ductile.
Step 3: Consider the options in the context of electrical wiring. Electrical wiring requires materials that can efficiently carry an electric current.
Step 4: Option 3 states that Copper is a metal and an excellent conductor of electricity, which aligns perfectly with its use in wiring.
✅ Copper is primarily used for electrical wiring because it is a metal and an excellent conductor of electricity, allowing it to efficiently transmit electrical current.