Chemistry Pre-Test (Unit 1 & 2)

Which of the following best describes atoms?

• Single celled organisms

• Smallest basic units of matter

• Parts of a nucleus

• Positively charged particles

Which of the following cannot be broken down by ordinary chemical means?

• Element

• Molecule

• Compound

• Bond

An ion is formed when an atom gains or loses:

• Protons

• Neutrons

• Bonds

• Electrons

Atoms connected by covalent bonds share:

• Pairs of electrons

• Ionic compounds

• Carbon and oxygen

• Hydrogen ions

Chemical reactions change substances into different substances by:

• Conserving matter between the substances

• Breaking and forming chemical bonds

• Strengthening electrical charges of substances

• Changing a solute into a solvent

Compared to the charge and mass of a proton, an electron has:

• The same charge and a smaller mass

• The same charge and the same mass

• An opposite charge and a smaller mass

• An opposite charge and the same mass

An element with 5 protons and 6 neutrons has an atomic number of:

• 5

• 6

• 8

• 11

Atoms of elements in a group on the periodic table have similar chemical properties. This similarity is most closely related to the atoms:

• Number of principal energy levels

• Number of valence electrons

• Atomic numbers

• Atomic masses

Which of the following indicates 4 molecules of water?

• H₂O

• 2 H₂O

• 4 H₂O

• H₄O₂

Write in scientific notation form: 127,000,000,000

• 12.7 x 10¹⁰

• 1.27 x 10¹¹

• 1.27 x 10¹⁰

• 12.7 x 10¹¹