20. Determine the oxidation number of the underlined element in H 2 P 2 O 7 . a.
ID: 831510 • Letter: 2
Question
20. Determine the oxidation number of the underlined element in H2P2O7.
a. +6
b. +7
c. +3
d. +4
e. +5
21. Which statement is false?
a. Ordinary chemical reactions do not involve changes in nuclei.
b. Atomic nuclei are very dense.
c. Nuclei are positively charged.
d. Electrons contribute only little to the mass of an atom.
e. The nucleus occupies nearly all the volume of an atom,
22. The atomic number of an element gives the number of______ and__________ in the atom while the mass number gives the total number of and .
a. neutrons, protons; neutrons, electrons
b. neutrons, electrons; protons, electrons
c. neutrons, electrons; neutrons, protons
d. protons, electrons; neutrons, electrons
e. protons, electrons; neutrons, protons
23. The atomic number of a certain element is 19, and its atomic weight is 39. An atom of the element contains
_________ protons,_________ neutrons, and the chemical symbol for the element is_______ .
a. 19, 19, F
b. 19, 20, F
c. 19, 20, K
d. 20, 19, K
e. none of these
24. Why is the atomic weight of chlorine 35.4527 instead of exactly 35?
a. Each chlorine atom has an odd number of protons.
b. There are two naturally occurring isotopes of chlorine.
c. Each isotope of chlorine has a different number of protons.
d. Every atom of chlorine has 18 neutrons.
e. Chlorine is a diatomic molecule.
25. What is the electron configuration of silicon, Si?
a. 1s22s22p63s23pi
b. 1s2lp62s22p4
c. 1s2lp62s22p2
d. 1s22s22p62d4
e. 1s22s22p63s23p4
26. Of the following, which element does not match its designation?
a. 38Sr representative metal
b. 49ln representative non-metal
c. 14Si metalloid
d. 74W d-transition metal
e. 90Th f-transition metal
27. Which of the following statements is false?
a. The effective nuclear charge experienced by an electron in an outer shell is less than the
actual nuclear charge.
b. Within a family (vertical group in the periodic table) of representative elements atomic
radii increase from top to bottom.
c. Electrons in inner shells screen, or shield, electrons in outer shells from the full effect of
the nuclear charge.
d. The atomic radii of representative elements decrease from left to right across a period
(horizontal row in the periodic table).
e. Transition elements have larger atomic radii than the preceding IA and IIA
elements in the same period because transition elements have electrons in their d orbitals.
28. Arrange the following elements in order of increasing first ionization energy.
Mg, Al, Si, P, S
a. Al < Mg < Si < S < P
b. Mg<Al<Si<P<S
c. Al< Mg < Si < P < S
d. Mg < Al< Si<S <P
e. Al< Mg < P < Si < S
29. Arrange the following set of ions in order of increasing ionic radii.
Ca2+, Cl -, K+, P3-, S2-
a. Ca2+ < K+ < P3- < S2- < Cl-
b. Ca2+ < K+ < Cl- < S2- < P3-
c. K+ < Cl- < Ca2+ < S2- < P3-
d. Cl- < S2- < P3- < Ca2+ < K+
e. P3- < S2- < Cl- < K+ < Ca2+
Explanation / Answer
20.a. +6
21b. Atomic nuclei are very dense.
22.e. protons, electrons; neutrons, protons
23.c. 19, 20, K
24.c. Each isotope of chlorine has a different number of protons.
25.a. 1s22s22p63s23pi
26.b. 49ln representative non-metal
27.e. Transition elements have larger atomic radii than the preceding IA and IIA
elements in the same period because transition elements have electrons in their d orbitals.
28.a. Al < Mg < Si < S < P
29.b. Ca2+ < K+ < Cl- < S2- < P3-
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.