Extra Credit e-homework Chapter 2


ANSWERS ARE GIVEN IN BOLD!

Start Date:     13 May 2008 at 04:00 PM
Due Date:     22 May 2008 at 01:00 AM
Student Access after Due Date:    Yes. View Only
Graded:    Yes

EOC Problem 2.16

In nature, the element neon exists as three different isotopes, Ne-20, Ne-21 and Ne-22. The atomic weight of neon is 20.2 amu. Which neon isotope predominates?
Ne-21

Ne-22

Ne-20

EOC Problen 2.56

Given a 16 mg sample of Rn-222 and a 4 mg sample of  I-131 which will decay to just 1 mg the fastest?

The half-life of Rn-222 is 3.8 days.
The half-life of I-131 is 8.1 days.
Rn-222

I-131

EOC Problem 2.48

Hg-197, a beta and gamma emitter, is used for brain scans. Write a balanced equation for the loss of 1 beta particle and 1 gamma ray from this radioisotope.
Hg-197   ----> ? + beta-particle + gamma ray
Tl-197

Au-197

Hg-198

Test Bank, Question 1

Which statement is incorrect?

Neutrons are found in the nucleus of the atom.

According to the atomic theory, all matter is composed of atoms.

Protons, neutrons, and electrons are subatomic particles.

Electrons have greater mass than protons.

Test Bank, Question 3

Atomic number and mass number differ in that atomic number is the number of _____ and mass number is _____ in an atom's nucleus.

protons/sum of protons and neutrons

protons/neutrons

neutrons/protons

protons/electrons

Test Bank, Question 5

The weighted average of all known isotopes of an element is the element's _____.

atomic number

atomic weight

mass number

isotope number

Test Bank, Question 10

 Mg-23 has how many protons, neutrons, and electrons?

12 protons, 11 neutrons, and 11 electrons

12 protons, 11 neutrons, and 12 electrons

12 protons, 23 neutrons, and 23 electrons

23 protons, 11 neutrons, and 23 electrons

Test Bank, Question 13

Which of the following contains elements that are nonlustrous, poor conductors of heat and electricity, and brittle.

nonmetals

metals

semimetals

transition metals

Test Bank, Question 15

Which form of ionizing radiation is most penetrating?

gamma

positron

alpha

beta

Test Bank, Question 18

Which of the substances listed is not an element?

air

iron

carbon

sodium

Test Bank, Question 23

Which is the proper notation for the oxygen isotope with atomic number 8 and a mass number of 16?

168O

O816

O168

816O

Test Bank, Question 26

Isotopes are two or more atoms with _____.

the same number of neutrons and protons.

the same number of neutrons, but different numbers of protons.

the same atomic mass.

the same number of protons, but different numbers of neutrons.

Test Bank, Question 30

Whereas x-ray works well for bones, the value of MRI imaging is _____.

it provides a clear picture of gamma rays produced within the tissue.

it provides images used in studies, such as monitoring sugar usage.

it provides a 3 dimensional view of bones.

it provides images of soft tissue.

Test Bank, Question 32

Which group contains the alkali metals?

3A

8A

1A

2A

Test Bank, Question 33

Which statement is correct?

Cl is an inert gas

Fe is a transition metal.

Mg is an alkali metal.

Cr is in period VIB.

Test Bank, Question 38

A sample of magnesium weighs 10 grams. How many moles of magnesium are there in the sample?

6 x 1023 moles

10 moles

60 x 1023 atoms

0.4 moles

Test Bank, Question 40

Most elements have radioisotopes. What is a radioisotope?

any isotope that can absorb nuclear particles.

an isotope that has a different atomic number.

an isotope that releases nuclear radiation.

an isotope that releases electrical radiation.

Test Bank, Question 42

Scandium-40 enters into a reaction in which a positron is emitted. Which is the correct equation for this reaction?

Sc-40   ---->   Ca-36  + positron

 Sc-40   ---->   Sc-36  + positron

Sc-40   ---->   Ca-40  + positron 

Sc-40   ---->   Sc-34  + positron 

Test Bank, Question 44

What is the minimum protection against exposure to beta particles?

A sheet of lead.

A thin sheet of plastic or metal.

None, beta particles are of low energy and cannot penetrate skin.

Gloves, a lab coat, or over a meter's distance from the source.

Test Bank, Question 46

A 35 mg dose of iodine-131 with a half-life of 8 days is administered to a patient. How long will it take for the iodine to decay so that there are only about 2 mg remaining?

64 days

8 days

16 days

32 days


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