Practice: A proton ___________:
a) Has one positive charge.
b) Has one AMU.
c) Is found in the nucleus of the atom.
d) Only a and b are true.
e) a, b, and c are true.
Concept #1: Atoms- Smallest Unit of Matter
Concept #2: Atoms- Smallest Unit of Matter
Example #1: Negatively charged particles of atoms with almost no mass are called:
Concept #3: Atoms- Smallest Unit of Matter
Concept #4: Atoms- Smallest Unit of Matter
Example #2: The atomic number of an element is equal to the number of:
Practice: The average oxygen atom has a mass number of 16 and an atomic number of 8. This means that the number of neutrons in this oxygen atom is:
a) 24.
b) 8.
c) 16.
d) 4.
e) 2.
Concept #5: Atoms- Smallest Unit of Matter
Practice: How many valence electrons does an atom with five total electrons have?
a) 5.
b) 7.
c) 3.
d) 2.
e) 1.
Practice: Which of the following is true about electron energy shells?
a) They represent regions around the nucleus in which the electrons orbit.
b) The shells closest to the nucleus contain electrons with higher energy.
c) They contain electrons of the same energy.
d) a and b only.
e) a and c only.
Concept #6: Atoms- Smallest Unit of Matter
Example #3: According to the octet rule, electron distribution in each shell of a neutral nitrogen atom (atomic number 7) is:
Practice: A neon atom (Ne) is unreactive for which of the following reasons?
a) It has 7 valence electrons.
b) It has 8 valence electrons.
c) Its valence shell is full of electrons.
d) It has 20 valence electrons.
e) b and c only.
Practice: How many electrons does an Oxygen atom need to fulfill the octet rule by filling its valence shell?
a) 8.
b) 4.
c) 1.
d) 2.
e) 6.
