2024-25 8th Grade Science PS.8.1.3

What statement is true about the eight elements on the periodic table termed metalloids?

• They are the only man-made elements.

• They all have the same number of protons and neutrons.

• They are the only naturally occurring elements.

• They have properties of both metals and nonmetals.

Is Javier's arrangement correct? Why or why not?

• Yes, because the reactivity of elements decreases as their atomic numbers decrease.

• Yes, because the reactivity of elements decreases from left to right on the periodic table.

• No, because the reactivity of elements decreases from right to left on the periodic table.

• No, because the reactivity of elements decreases as their atomic masses increase.

On the periodic table, atomic mass A. increases up a group. B. decreases down a group. C. decreases across a period from left to right. D. increases across a period from left to right.

• increases up a group

• decreases down a group

• decreases across a period from left to right

• increases across a period from left to right

The periodic table is organized into vertical groups of

• elements with similar properties.

• compounds with different properties.

• elements with all the same chemical properties.

• compounds with all different physical properties.

A majority of the 118 elements on the periodic table are classified as

• liquids

• metals

• metalloids

• non-metals

The diagram below shows the block for cobalt (Co) as seen on the periodic table. What is the atomic number of cobalt?

• A. 27

• B. 28

• C. 58.693

• D. 58.933

The pictures show two elements from the periodic table. These two elements have similar properties and behave the same in a chemical reaction. How should they be placed on the periodic table?

• They should be placed in the same group with K on top and Na below.

• They should be placed in the same group with Na on top and K below.

• They should be placed in the same period with K on top and Na below.

• They should be placed in the same period with Na on top and K below.

Select four of the following that have properties similar to neon. Pick up to 6 answers.

• fluorine

• argon

• xenon

• radon

• krypton

When sodium is mixed with water, an explosion takes place. Based on its location on the periodic table, how will potassium behave with water?

• Potassium, which shares similar properties with sodium, will explode in water.

• Potassium, which shares similar properties with sodium, will not explode in water.

• Potassium, which does not share similar properties with sodium, will explode in water.

• Potassium, which does not share similar properties with sodium, will not explode in water.

Look closely at the illustration below, which shows a part of the periodic table. Which two elements have properties that are the most similar?

• C and F

• He and Ne

• Al and Si

• N and S