Q1. What is the atomic mass for potassium?

Background

Topic: Atomic Structure and Periodic Table

This question tests your knowledge of the periodic table, specifically the atomic mass of elements.

Key Terms:

• Atomic mass: The weighted average mass of the atoms in a naturally occurring element, usually found below the element symbol on the periodic table.

• Potassium: Chemical symbol K.

Step-by-Step Guidance

1. Locate potassium (K) on the periodic table.

2. Identify the atomic mass value listed for potassium (usually a decimal number below the symbol).

3. Compare the value you find to the answer choices provided.

Try solving on your own before revealing the answer!

Q2. Which of the following is an ionic compound?

Background

Topic: Chemical Bonding

This question tests your ability to distinguish between ionic and covalent compounds.

Key Terms:

• Ionic compound: Formed between metals and nonmetals, involving the transfer of electrons.

• Covalent compound: Formed between nonmetals, involving the sharing of electrons.

Step-by-Step Guidance

1. Identify which elements in each compound are metals and which are nonmetals.

2. Recall that ionic compounds are typically formed between a metal and a nonmetal.

3. Check each answer choice to see which one fits this pattern.

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Q3. Without using a calculator, solve the following problem:

Background

Topic: Scientific Notation and Exponents

This question tests your ability to manipulate numbers in scientific notation and apply exponent rules.

Key Terms and Formulas:

• Scientific notation: A way to express very large or small numbers using powers of ten.

• Exponent rules: and

Step-by-Step Guidance

1. Multiply the two numbers in the numerator: .

2. Apply the exponent rule to combine the powers of ten.

3. Square the result from step 2.

4. Divide by using exponent rules.

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Q4. Identify the common substance that has the lowest density.

Background

Topic: Density and Properties of Matter

This question tests your understanding of the concept of density and the relative densities of common substances.

Key Terms:

• Density:

• Common substances: sugar, ethanol, table salt, aluminum, titanium

Step-by-Step Guidance

1. Recall the general densities of the listed substances (solids, liquids, metals).

2. Compare the densities: metals are usually denser than liquids and most solids.

3. Identify which substance is a liquid and typically has a lower density than the others.

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Q5. Which of the following contains the fewest atoms? (No calculation needed)

Background

Topic: Moles, Atomic Mass, and Counting Atoms

This question tests your ability to reason about the number of atoms in equal masses of different elements.

Key Terms:

• Mole: $1 particles (Avogadro's number)

• Atomic mass: The mass of one mole of atoms of an element (in grams)

Step-by-Step Guidance

1. Recall that the number of atoms in a given mass depends on the atomic mass of the element.

2. Elements with higher atomic mass will have fewer atoms in the same mass compared to elements with lower atomic mass.

3. Compare the atomic masses of Kr, Li, Ar, Na, and Cs to determine which is the largest.

Try solving on your own before revealing the answer!