Question 1:

The Periodic Table consists of elements arranged in order of atomic number (the number of protons in the nucleus of an atom).

• Mass number is not used because it refers to the total number of protons and neutrons, which can vary due to isotopes.

• Radius and reactivity are properties that show trends across the table but are not the basis for the arrangement.

So, the correct answer is atomic number.

*These A.I. responses have been individually checked to ensure they match the accepted answer, but explanations may still be incorrect. Responses may give guidance but the A.I. might not be able to answer the question! This is particularly the case for questions based on diagrams, which the A.I. typically cannot interpret.
Grade Gorilla uses Gemini, Deepseek and a range of other A.I. chatbots to generate the saved responses. Some answers have had human intervention for clarity or where the A.I. has not been able to answer the question.

Question 2:

The correct answer is A. a group.

• A group is a vertical column in the Periodic Table. Elements in the same group have similar chemical properties because they have the same number of outer electrons.

• A period is a horizontal row.

• Symbol and element are not names for columns or rows.

*These A.I. responses have been individually checked to ensure they match the accepted answer, but explanations may still be incorrect. Responses may give guidance but the A.I. might not be able to answer the question! This is particularly the case for questions based on diagrams, which the A.I. typically cannot interpret.
Grade Gorilla uses Gemini, Deepseek and a range of other A.I. chatbots to generate the saved responses. Some answers have had human intervention for clarity or where the A.I. has not been able to answer the question.

Question 3:

The correct answer is C. outer electrons.

Elements in the same group (vertical column) of the Periodic Table have the same number of electrons in their outer shell (also called valence electrons). This is why they exhibit similar chemical properties.

• Neutrons (A) can vary even within the same element (isotopes).

• Protons (B) define the element itself; elements in a group have different proton numbers.

• Occupied electron shells (D) are the same for elements in the same period (horizontal row), not the same group.

*These A.I. responses have been individually checked to ensure they match the accepted answer, but explanations may still be incorrect. Responses may give guidance but the A.I. might not be able to answer the question! This is particularly the case for questions based on diagrams, which the A.I. typically cannot interpret.
Grade Gorilla uses Gemini, Deepseek and a range of other A.I. chatbots to generate the saved responses. Some answers have had human intervention for clarity or where the A.I. has not been able to answer the question.

Question 4:

The correct answer is B. occupied electron shells.

• Elements in the same period (horizontal row) have the same number of occupied electron shells (energy levels). For example, all elements in Period 3 have 3 electron shells.

• Reactions (A) are not a fixed property of a period.

• Neutrons (C) can vary even within the same element (isotopes).

• Outer electrons (D) are the same for elements in the same group, not the same period.

*These A.I. responses have been individually checked to ensure they match the accepted answer, but explanations may still be incorrect. Responses may give guidance but the A.I. might not be able to answer the question! This is particularly the case for questions based on diagrams, which the A.I. typically cannot interpret.
Grade Gorilla uses Gemini, Deepseek and a range of other A.I. chatbots to generate the saved responses. Some answers have had human intervention for clarity or where the A.I. has not been able to answer the question.

Question 5:

The correct answer is A. a metal with 3 occupied electron shells and 2 outer shell electrons.

Here's the reasoning:

• Period 3 means the element has 3 occupied electron shells (energy levels).

• Group 2 means it has 2 electrons in its outer shell.

• Elements in Group 2 are the alkaline earth metals (e.g., magnesium, calcium), so it is a metal.

Thus, it is a metal with 3 shells and 2 outer electrons.

*These A.I. responses have been individually checked to ensure they match the accepted answer, but explanations may still be incorrect. Responses may give guidance but the A.I. might not be able to answer the question! This is particularly the case for questions based on diagrams, which the A.I. typically cannot interpret.
Grade Gorilla uses Gemini, Deepseek and a range of other A.I. chatbots to generate the saved responses. Some answers have had human intervention for clarity or where the A.I. has not been able to answer the question.

Question 6:

Ions with a 2+ charge are formed by elements in Group 2 (the alkaline earth metals). They lose their 2 outer electrons to achieve a stable electron configuration.

*These A.I. responses have been individually checked to ensure they match the accepted answer, but explanations may still be incorrect. Responses may give guidance but the A.I. might not be able to answer the question! This is particularly the case for questions based on diagrams, which the A.I. typically cannot interpret.
Grade Gorilla uses Gemini, Deepseek and a range of other A.I. chatbots to generate the saved responses. Some answers have had human intervention for clarity or where the A.I. has not been able to answer the question.

Question 7:

Ions with a 1– charge are formed by elements in Group 7 (the halogens). They gain 1 electron to complete their outer shell.

*These A.I. responses have been individually checked to ensure they match the accepted answer, but explanations may still be incorrect. Responses may give guidance but the A.I. might not be able to answer the question! This is particularly the case for questions based on diagrams, which the A.I. typically cannot interpret.
Grade Gorilla uses Gemini, Deepseek and a range of other A.I. chatbots to generate the saved responses. Some answers have had human intervention for clarity or where the A.I. has not been able to answer the question.

Question 8:

The correct answer is B. they have a full outer electron shell.

Noble gases (Group 8/0) are unreactive because they have a complete outer shell of electrons (usually 8 electrons, except helium which has 2). This stable electron configuration means they have little tendency to gain, lose, or share electrons, making them chemically inert.

• A is true (they are monatomic gases) but is not the reason for their unreactivity.

• C is false—they have full outer shells, not empty ones.

• D describes some physical properties but does not explain their lack of chemical reactivity.

*These A.I. responses have been individually checked to ensure they match the accepted answer, but explanations may still be incorrect. Responses may give guidance but the A.I. might not be able to answer the question! This is particularly the case for questions based on diagrams, which the A.I. typically cannot interpret.
Grade Gorilla uses Gemini, Deepseek and a range of other A.I. chatbots to generate the saved responses. Some answers have had human intervention for clarity or where the A.I. has not been able to answer the question.

Question 9:

The correct answer is C. a non-metal in period 2 and group 6.

Here's the reasoning:

• Period: The number of occupied electron shells is 2 (from the configuration 2,6), so it is in Period 2.

• Group: The number of outer electrons is 6 (the second number in 2,6), so it is in Group 6 (or Group 16 by modern IUPAC numbering).

• Metal/Non-metal: Elements in Group 6 with only 2 shells (Period 2) include oxygen and sulfur, which are non-metals.

Thus, it is a non-metal in period 2 and group 6.

*These A.I. responses have been individually checked to ensure they match the accepted answer, but explanations may still be incorrect. Responses may give guidance but the A.I. might not be able to answer the question! This is particularly the case for questions based on diagrams, which the A.I. typically cannot interpret.
Grade Gorilla uses Gemini, Deepseek and a range of other A.I. chatbots to generate the saved responses. Some answers have had human intervention for clarity or where the A.I. has not been able to answer the question.

Question 10:

The correct answer is D. good conductivity and pH 10.

Here's the reasoning:

• Metals are good conductors of electricity (due to delocalized electrons).

• Metal oxides are basic in nature, so when dissolved in water they form alkaline solutions with a pH greater than 7 (e.g., pH 10).

Option D matches both properties: good conductivity (metal) and pH 10 (basic oxide, confirming it is a metal).

• Options A and B have poor conductivity (non-metal).

• Option C has good conductivity (metal) but pH 4 (acidic, which is characteristic of a non-metal oxide).

*These A.I. responses have been individually checked to ensure they match the accepted answer, but explanations may still be incorrect. Responses may give guidance but the A.I. might not be able to answer the question! This is particularly the case for questions based on diagrams, which the A.I. typically cannot interpret.
Grade Gorilla uses Gemini, Deepseek and a range of other A.I. chatbots to generate the saved responses. Some answers have had human intervention for clarity or where the A.I. has not been able to answer the question.