Page 63 - Chemistry eBook

Li-7 7.02 92.5
or o
NH 2N22
Answer all questions in this part.
Directions (31–50): For each statement or question, record on your s
word or expression that, of those given, best completes the statement or
may require the use of the 2011 Edition Reference Tables for Physical S Sample Regents Questions
31 An atom in the ground state has two electrons in its first shell and six electrons in its second shell. What is the total number of protons in the nucleus of this atom?
(1) 5 (3) 7 (2) 2 (4) 8
(1) 2-8-18-6 (3) 2-8-17-7 (2) 2-8-18-7 (4) 2-8-17-8
35
Which ge elements atomic n
(1) incre (2) incre (3) decre (4) decre
Given th
Jan 2012 #31
32 A bromine atom in an excited state could have an electron configuration of
36
33 The atomic masses and the natural abundances
Choice #4
of the two naturally occurring isotopes of
Explanation: The atom has 8 electrons. (2+6=8)
lithium are shown in the table below.
Number of electrons in an atom = number of protons in the atom Therefore, if the atom has 8 electrons, it must also have 8 protons.
Isotope
Li-6
Atomic Mass
Natural Abundance (%)
Which m represent
(1) C2H (2) C H
Lithium Isotopes
Answer
(u)
6.02 7.5
parate ans answers t tting/Che
neral tren are consi mber?
sing atom
sing elect asing atom asing first
formula f
O H
lecular fo this comp
O2 and C O and C
e
h
em
d d
ai ar
i eo
u
UNIT 2: ATOMIC STRUCTURE © 63