Regents Chemistry June exam practice

Front

What is the mass of a proton in atomic mass units?

Back

Approximately 1 atomic mass unit (amu).

Front

What property decreases in Group 17 elements as atomic number increases?

Back

Electronegativity.

Front

What is an endothermic physical change?

Back

A change that absorbs heat, such as CO₂(s) → CO₂(g).

Front

Which atom has a stable valence electron configuration in the ground state?

Back

Argon (Ar).

Front

What do butane and methylpropane have in common?

Back

They have the same molecular formula (C4H10) but different properties.

Front

Define atomic radius.

Back

The distance from the nucleus of an atom to the outermost shell of electrons.

Front

What is electronegativity?

Back

The ability of an atom to attract electrons in a chemical bond.

Front

What is the difference between physical and chemical changes?

Back

Physical changes do not alter the chemical composition, while chemical changes do.

Front

What is an isomer?

Back

Compounds with the same molecular formula but different structural arrangements.

Front

What is the significance of the octet rule?

Back

Atoms tend to gain, lose, or share electrons to achieve a full outer shell of 8 electrons.