Atoms Isotopes Average Atomic Mass

Development of Atom

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Atoms – 10 Points

QUESTION:

•What are the three subatomic particles that make up the atom?

ANSWER:

•Protons, Neutrons, Electrons

Atoms – 20 Points

QUESTION:

•What is calculated by adding the number of protons and the number of neutrons of an element?

ANSWER:

•Mass Number

Atoms – 30 Points

QUESTION:•“Mass is neither created nor destroyed” is what law and who discovered it?

ANSWER:•Law of Conservation of Mass by Antoine Lavoisier

Atoms – 40 Points

QUESTION:

•How many electrons can the third energy level hold?

ANSWER:

•18

Atoms – 50 Points

QUESTION:

•What is the Law of Definite Composition?

ANSWER:

•The law that a chemical compound contains the same elements in exactly the same proportions by mass regardless of the size of the sample or source of the compound.

Isotopes – 10 Points

QUESTION:

•What causes the difference in the masses of isotopes?

ANSWER:

•The Neutrons

Isotopes – 20 Points

QUESTION:

•What is the mass number of an element that contains 41 protons and 44 neutrons?

ANSWER:

•85

Isotopes – 30 Points

QUESTION:

•10250Sn has how many protons?

ANSWER:

•50

Isotopes – 40 Points

QUESTION:

•What is the nuclear symbol for the isotope of oxygen which has 9 neutrons and 10 electrons?

ANSWER:

•178O2-

Isotopes – 50 Points

QUESTION:

•What are the three isotopes of Hydrogen?

ANSWER:

•Protium, dueterium, tritium

Average Atomic Mass – 10 Points

QUESTION:

•What is the average atomic mass of Carbon if 98.89% exists as 12C and 1.11% exists as 13C?

ANSWER:

•12.01 ~ 12 amu

Average Atomic Mass – 20 Points

QUESTION:•What is the average atomic mass of Boron if it exists as

19.90% 10B and 80.10% 11B? 

ANSWER:

•10.801 ~ 11 amu

Average Atomic Mass – 30 Points

QUESTION:

•What is the average atomic mass of Calcium if 24% exists as 41Ca, 60% exists as 40Ca, and 16% exists as 39Ca?

ANSWER:

•40.1 ~ 40. amu

Average Atomic Mass – 40 Points

QUESTION:•Cadmium has five common isotopes: 110Cd (8.0%), 112Cd (7.8%), 113Cd (73.4%), 114Cd (5.5%), 115Cd (5.3%). What is the average atomic mass of cadmium? 

ANSWER:

• 112.843 ~ 113 amu

Average Atomic Mass – 50 Points

QUESTION:

•Lithium has two isotopes with atomic masses of 6.674 amu and 7.254 amu. Estimate the abundance of these two isotopes if the atomic mass of naturally occurring lithium is 6.941.

ANSWER:•53.97%, 46.03%

Development of Atom – 10 Points

QUESTION:

•Who discovered the electron in 1897 by using a cathode ray tube?

ANSWER:

•J.J. Thomson

Development of Atom – 20 Points

QUESTION:

•Who determined the exact charge of an electron through the Oil Drop Experiment?

ANSWER:

•Robert Milikan

Development of Atom – 30 Points

QUESTION:

•Who discovered energy levels?

ANSWER:

•Niels Bohr

Development of Atom – 40 Points

QUESTION:

•Who discovered the neutron?

ANSWER:

•Chadwick

Development of Atom – 50 Points

QUESTION:

•Who realized there were positively charged particles moving in the direction opposite to cathode rays, which caused them to discover the proton?

ANSWER:

•Goldstein and Wein