Answers TX-Integrated Physics and Chemistry A-CRUnit Test

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Which element has a complete valence electron shell?

selenium (Se)

oxygen (O)

fluorine (F)

argon (Ar)

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Krypton is named after the Greek word that means “secret.” Which explains why krypton was most likely given this name?

Krypton is a halogen, so it is a secret element because it is always part of a compound and is difficult to find by itself.

Krypton is a halogen, so it should be kept secret because it is so reactive and toxic.

Krypton is a noble gas, so it was difficult for chemists to find it, as though it was a secret.

Krypton is a noble gas, so it secretly bonds with every type of element without showing it.

Which statement best explains why radon and krypton do not bond easily with other elements?

They have many electron shells, so their protons do not attract electrons strongly.

They have eight electrons in their valence shells, so they are stable without gaining or losing electrons.

Their valence shells are empty, so they do not need to bond with other elements to be more stable.

Their valence shells are so close to the protons in the nucleus that bonding cannot happen like in other elements.

What property do all of the group 18 elements have that makes them stand out from other elements?

They are the only nonmetals that are liquid at room temperature.

They are the only nonmetals that are solid at room temperature.

They are very likely to bond with any element, whether it is metallic or not.

They are very unlikely to bond with any element, whether it is metallic or not.

Eriq, a chemist, is running tests with four unknown elements. He has found that they all bond the same way, so he knows that they are in the same group on the periodic table of elements. The table shows other properties that Eriq observed.

15.

16.

17.

18.

Where are the most reactive nonmetal elements found on the periodic table?

at the top of group 17

at the bottom of group 17

at the top of group 18

at the bottom of group 18

Which describes any substance that shatters or breaks easily?

malleable

brittle

volatile

ductile

Which compound forms a powerful acid and also contains a halogen?

H2S

HBr

Li2O

LiBr

What is the most likely reason that nonmetals are electrical insulators?

Since valence shells are mostly empty in nonmetal atoms, the atoms attract and hold any electrons they can in order to fill their valence shells.

Since valence shells in nonmetal atoms are almost full, the atoms attract electrons and hold them tightly to fill their valence shells.

Since all nonmetals have valence shells that are full, they hold electrons tightly to avoid changing.

Since all nonmetals have valence shells that are completely empty, they do not attract or release any electrons.

Looking at the same nonmetal group on the periodic table, how does the reactivity of an element in period 2 compare to the reactivity of an element in period 4?

The period 2 element would be more reactive because the attractive force of protons is stronger when there are fewer neutrons interfering.

The period 2 element would be more reactive because the attractive force of protons is stronger when electrons are attracted to a closer electron shell.

The period 4 element would be more reactive because the attractive force of protons is stronger when there are more neutrons helping.

The period 4 element would be more reactive because the attractive force of protons is stronger when electrons are attracted to a farther electron shell.

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