Review- Elements, compounds, chemical formulas

Front

What is an element?

Back

An element is a pure substance that cannot be broken down into simpler substances by chemical means. It consists of only one type of atom.

Front

What is a compound?

Back

A compound is a substance formed when two or more different elements are chemically bonded together. For example, water (H2O) is a compound made of hydrogen and oxygen.

Front

What is a chemical formula?

Back

A chemical formula is a way of expressing the composition of a substance using symbols for its constituent elements and numbers to indicate the ratio of atoms.

Front

How many atoms are in one molecule of serotonin (C₁₀H₁₂N₂O)?

Back

There are 25 atoms in one molecule of serotonin.

Front

What are the characteristics of metals?

Back

Metals are typically shiny, malleable, ductile, and good conductors of heat and electricity.

Front

What is the periodic table?

Back

The periodic table is a tabular arrangement of chemical elements, organized by increasing atomic number, which shows the relationships between them.

Front

What is the significance of the atomic number?

Back

The atomic number represents the number of protons in the nucleus of an atom and determines the element's identity.

Front

What is a gas at room temperature with no flammability?

Back

Nitrogen (N2) is a gas at room temperature and is non-flammable.

Front

What elements are present in the formula CaCO3?

Back

The elements present in CaCO3 are calcium (Ca), carbon (C), and oxygen (O).

Front

What is a metalloid?

Back

Metalloids are elements that have properties of both metals and nonmetals. They are semiconductors of electricity.