Front

What is the mass number of an isotope?

Back

The mass number is the total number of protons and neutrons in an atom's nucleus.

Front

How do you calculate the mass number of an element?

Back

Mass number = Number of protons + Number of neutrons.

Front

What is VSEPR theory?

Back

VSEPR (Valence Shell Electron Pair Repulsion) theory predicts the shape of molecules based on the repulsion between electron pairs.

Front

What is the molecular shape of NBr3 according to VSEPR theory?

Back

Trigonal-pyramidal.

Front

What is sublimation in terms of phase changes?

Back

Sublimation is the process where a solid changes directly into a gas without passing through the liquid phase.

Front

What type of change occurs when carbon dioxide sublimates?

Back

Physical change.

Front

Define ductility in materials science.

Back

Ductility is the ability of a material to be stretched into a wire.

Front

What is the difference between ductility and malleability?

Back

Ductility refers to stretching into wires, while malleability refers to being hammered or rolled into sheets.

Front

What is a chemical change?

Back

A chemical change involves a transformation that alters the chemical composition of a substance.

Front

Give an example of a chemical change.

Back

Examples include oxidation, tarnishing, and digestion.