Introduction to Chemistry of Life

Which of the following statements is incorrect?

• Matter may be solid, liquid or gas. 
• Elements can be decomposed into simpler substances by ordinary chemical reactions. 
• A compound is any substance composed of atoms of two or more different elements that are chemically combined
•  A molecule is the combination of two or more atoms held together by covalent bonds. 

Which of the following statements is not true?

• Protons are positively charged particles which contribute to the weight of an atom. 
• The overall charge of the atom’s nucleus is always positive.
• The number of electrons always equals the number of protons in a neutral atom. 
• The bigger difference in neutrons in the isotope, the more stable it becomes. 

A cation is formed when an atom loses an electron or electrons to another atom creating an overall positive charge. 

• True
• False

The atomic number refers to the

• mass of an atom
• number of protons in an atom
• number of both protons and neutrons in an atom
• number of neutrons in an atom

Radioactive isotopes have an excess number of neutrons.

• True
• False

Tags

NGSS.HS-PS1-8

Which of the following is not a compound?

• NaCl
• C₆H₁₂0₆
• H₂0
• o₂

The negative subatomic particle in an atom is the

• neutron
• proton
• electron
• both neutrons and electrons

The nucleus of an atom contains

• neutrons and protons
• neutrons and electrons
• protons and electrons
• protons only

The atomic weight of an atom is determined by the weight of

• neutrons and protons
• neutrons and electrons
• protons and electrons
• neutrons only

Magnesium has 12 protons.  How many electrons are in the third energy level?

• 2
• 4
• 6
• 8