ch 11 study guide answer key

8/3/2019 ch 11 Study Guide Answer Key

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Name: ______________________________ Date: __________________ Period:_____________

Chapter 11 Study Guide(due Wednesday)

1.) Electrons are found in the__electron clouds____ of an atom.2.) All atoms of the same element contain the same number of_protons_____.3.) ______Electrons______ have no electric charge.4.) The _____mass_______ of an element is the number of protons and neutrons in the

nucleus.

5.) The ____atomic mass_______ is an average of the masses of all naturally occuringisotopes of an element.

6.) How many protons does an atom with an atomic number of 23 and mass number of 51have?

Protons:______23_______7.) What determines the identity of an element? Atomic #8.) Isotopes exist because atoms of the same element can have different numbers of

______neutrons__________.9.) What did Democritis, Dalton, Thomson, Rutherford, and Bohr all have in common?

They all contributed ideas for the atomic theory________________________________________________________________________________________________________________________________________________________

10.) An atom of gold with 79 protons, 79 electrons and 118 neutrons would have amass number of __________197 amu_______.

11.) The smallest particle into which an element can be divided and still be the samesubstance is a(n) ________atom__________.

12.) Mass number includes ______protons_____ and _____neutrons____________.13.) Which part of an atom has the least mass? ____electrons____________14.) Name the charges for the following:

Protons:________+__________ Neutrons:___no charge_________ Electrons:___-_____ positive negative


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15.) The fourforces found in all atoms are________electromagnetic force______ __________gravitational force___________________strong force_________ __________weak force__________

16.) The ________________________________holds the electrons around thenucleus.

17.) The Greek philosopher who gave the atom its name was_________Democritis______________.

18.) How did people respond when Democritus proposed the idea of an uncuttableparticle because ofAristotle?They didn't believe Democritis, because Aristotledisagreed.

19.) What Thomson called corpuslces are now called _electrons______.20.) A representation of an object or system is a(n) ____model___________.21.) Who performed an experiment proving the existence of an atomic nucleus?

_____Rutherford___________22.) Who suggested that electrons travel around the nucleus in definite paths?

_________Bohr____________23.) The current model of the atom suggests that ____Electrons do not travle in

paths they surround the nucleus in clouds.__________________24.) Atoms are composed of: (3 things)

____protons__________ ____neutrons _________ ______electrons_________25.) Neutrons are particles that _______neutrally charged (no charge) and inside the

nucleus, hold protons in the nucleus._________________________________________26.) Electrons are particles that _______negatively charged, around outside of

nucleus and cancel out positive protons______________________________________27.) Define an ion._____a charged atom due to a gain or lost electron28.) Which of the following sets of particles represents an ion?

a. 20 protons, 19 neutrons, 20 electrons * b. 19 protons, 19 neutrons, 18 electrons*****An atom of nickel has an atomic number of 28 and a mass number of 58.

29.) How many protons are in the atom of nickel? ______28___________30.) How many electrons are in the atom of nickel? ______28__________31.) How many neutrons are in the atom of nickel? ______30___________


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32.) Illustrate an atom ofHelium-3 below.

33.) What is the atom's atomic number? _______2_______34.) What is the atom's atomic mass? _________3_______(normally 4)35.) Magnesium occurs naturally as 79% Magnesium-24, 10% Magnesium-25, and

11% Magnesium-26. What is the atomic mass of Magnesium?24(.79)=18.96

25(.1)=2.5 = add together 24.32 amu26(.11)=2.86

36.) Lithium occurs naturally as 92.5 % Lithium-7 and 7.5% Lithium-6. What is theatomic mass of Lithium?7(.925)=6.475

6(.075)=.45 = add together 6.925 amu

Pick any 2 elements and provide the following (use the periodic table):Name: Name:

Atomic #: Atomic #:

Atomic mass: Atomic mass:

# of protons: # of protons:

# of neutrons: # of neutrons:

# of electrons: # of electrons:

One isotope: One isotope:

ch 11 study guide answer key

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