Exploring Atoms and Elements

What is the smallest unit of an element?

• molecule

• compound

• ion

• atom

Define a molecule and give an example.

• Carbon Dioxide (CO2)

• Water (H2O)

• Oxygen (O2)

• Sodium Chloride (NaCl)

What is the difference between an element and a compound?

• Elements can be broken down into simpler substances, whereas compounds cannot.

• An element can be made of multiple types of atoms, while a compound is made of a single type of atom.

• An element consists of one type of atom, while a compound consists of two or more different types of atoms chemically bonded.

• A compound is a pure substance, while an element is a mixture of different substances.

How are elements organized in the periodic table?

• Elements are organized by atomic number, periods, and groups.

• Elements are organized by their discovery date.

• Elements are organized by their popularity and usage.

• Elements are organized by color and shape.

What information does a chemical symbol provide?

• A chemical symbol shows the number of protons in an element.

• A chemical symbol represents the state of matter of an element.

• A chemical symbol indicates the atomic mass of an element.

• A chemical symbol provides the identity of an element.

Write the chemical formula for water.

• H2O2

• O2H

• H2O3

• H2O

What are the properties of metals?

• Metals are non-conductive and dull in appearance.

• Metals are always brittle and break easily.

• Metals have low melting points and are not shiny.

• Metals are conductive, malleable, ductile, lustrous, and have high melting points.

Name two nonmetals and their properties.

• Oxygen and Sulfur

• Hydrogen and Helium

• Iron and Copper

• Carbon and Silicon

How does reactivity vary among different groups in the periodic table?

• Reactivity increases across a period from left to right.

• Reactivity decreases down Group 1 and Group 17.

• Reactivity increases down Group 1 (alkali metals) and Group 17 (halogens), while it decreases across a period from left to right.

• Reactivity is constant across all groups in the periodic table.

What is an ion?

• A molecule that contains only nonmetals.

• An ion is a charged atom or molecule.

• A neutral atom with no charge.

• A type of chemical bond between atoms.