Chemistry Review (Ch 2)

How do isotopes of the same element differ from each other?

• # protons
• # electrons
• # neutrons
• valence electron distribution

What does the reactivity of an atom depend on?

• number of valence shells in the atom
• number of electrons in each orbital in the atom
• presence of unpaired electrons in the outer valence shell of the atom
• number of orbitals found in the atom

How many electrons does an atom of Phosophorus have in its valence shell?

• 4
• 5
• 16
• 32

How many electrons does an atom of sulfur have in its valence shell?

• 32
• 16
• 6
• 4

The mass number of an element can be easily approximated by adding together the number of ____ in an atom of that element.

• protons and neutrons
• protons and electrons
• isotopes
• ions

What is the difference between covalent bonds and ionic bonds?

• ionic is sharing electrons; covalent is transferring electrons
• Covalent bonds involve the sharing of protons between atoms, and ionic bonds involve the sharing of electrons between atoms.
• There is a difference? 
• Covalent bonds involve the sharing of electrons between atoms, and ionic bonds involve the electrical attraction between atoms.

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-3

Explains most specifically the attraction one water molecule to another water molecule.

• polar covalent
• hydrogen bonds
• ionic bonds
• covalent bonds

About 25 of the 92 natural elements are known to be essential to life. Which four of these 25 elements make up approximately 96% of living matter?

• carbon, oxygen, sulfur, calcium
• carbon, sodium, chlorine, nitrogen
• carbon, hydrogen, nitrogen, oxygen
• oxygen, hydrogen, calcium, sodium

What results from an unequal sharing of electrons between atoms?

• a nonpolar covalent bond
• a polar covalent bond
• a hydrogen bond
• a hydrophobic interaction

Electrons exist only at fixed levels of potential energy. However, if an atom absorbs sufficient energy, a possible result is that

• an electron may move to an electron shell farther out from the nucleus.
• the atom would become a negatively charged ion, or anion.
• the atom may become a radioactive isotope.
• an electron may move to an electron shell closer to the nucleus.