Atomic Theory Worksheet

Historical Development of the modern model of the atom.

Draw below the model of the atom proposed be the following individuals

Dalton (1800) Thompson (1897) Bohr (1913)

How did Thompson’s model differ from Dalton’s model?

The gold foil experiment resulted in two major discoveries which were made about the structure of the atom. What were they?

1.

2.

How is an atomic spectra produced? Use the terms ground and excited state electrons in your answer.

How does the Bohr model represent electrons around the central nucleus? Why (think of spectra)?

The modern model of the atom is called the wave mechanical model. In the wave mechanical model electrons are located around the nucleus based on the probability of finding an electron in a certain area. These areas are calleda. shells b. orbitals c. rings d. waves

Protons, neutrons, electrons

How many protons neutrons and electrons are in each of the following atoms?

Protons Neutrons Electrons

Carbon-12 ______ ______ ___________

Chlorine-35 ______ ______ ___________

Iron-55 ______ ______ ___________

Carbon-14 ______ ______ ___________

Chlorine-37 ______ ______ ___________

How many total electrons are surrounding the following ions?

Na+ ___________ P-3 ___________

N-3 __________ Cr+6 ___________

H+ ___________ S-2 ___________

Average Atomic Mass/Isotopes

Define Isotope-

Define Atomic Mass-

Draw diagrams of the following nuclei to show how the following isotopes differ from each other.

= Neutron = Proton

lithium-6 and lithium-7

boron-10 and boron-11

Calculate the average atomic mass given the following isotopes and their percent abundances.

Boron-10 19.78%; Boron-11 80.22%

Te-122 0.089%; Te-124 2.46%; Te-126 5.48%; Te-128 91.97%

There are three isotopes of element X. X-45, X-46, and X-48. If the atomic mass of element X is 45.23 which isotope is most common? Why?

Electron configuration and lewis dot structures

Define valence electron-

How many energy levels and valence electrons are in the following electron configurations?

Energy levels valence electrons

2-8-2 ___________ ______________

1 ___________ ______________

2-8-18-4 ___________ ______________

2-8-18-14-1 ___________ ______________

Which of the following represents an excited state electron configuration?

2-8-8-1 2-8-7-1 2-7-8-2 2-8-8-2

1-8-2 2-8-2 2 2-8-5

Which elements are represented by the electron configurations above (all electron configurations above are for neutral atoms)?

_________ _________ _________ _________

________ _________ __________ _________

Which electron configuration represents an atom of aluminum in the excited state?

2-7-4 2-8-3 1-8-5 2-8-7-1 2-8-1-3

Which electron configuration represents the ion Ca2+?

2-8-8-2 2-8-8 2-7-8-1 2-8-8-1 1-8-8-2

Draw the Lewis dot structure for elements 1-10

Selected Multiple Choice Questions

Atomic Theory

Matching

Match each item with the correct statement below.a. proton d. electronb. nucleus e. neutronc. atom

____ 1. a positively charged subatomic particle____ 2. a negatively charged subatomic particle____ 3. a subatomic particle with no charge____ 4. the central part of an atom, containing protons and neutrons

Match each item with the correct statement below.a. mass number d. atomic massb. atomic mass unit e. isotopec. atomic number

____ 5. atoms with the same number of protons, but different numbers of neutrons in the nucleus of an atom

____ 6. the total number of protons and neutrons in the nucleus of an atom____ 7. the number of protons in the nucleus of an element____ 8. the weighted average of the masses of the isotopes of an element

Multiple ChoiceIdentify the choice that best completes the statement or answers the question.

____ 9. Which of the following is true about subatomic particles?a. Electrons are negatively charged and are the heaviest subatomic particle.b. Protons are positively charged and the lightest subatomic particle.c. Neutrons have no charge and are the lightest subatomic particle.d. The mass of a neutron nearly equals the mass of a proton.

____ 10. All atoms are ____.a. positively charged, with the number of protons exceeding the number of electronsb. negatively charged, with the number of electrons exceeding the number of protonsc. neutral, with the number of protons equaling the number of electronsd. neutral, with the number of protons equaling the number of electrons, which is equal to the

number of neutrons____ 11. The particles that are found in the nucleus of an atom are ____.

a. neutrons and electrons c. protons and neutronsb. electrons only d. protons and electrons

____ 12. As a consequence of the discovery of the nucleus by Rutherford, which model of the atom is thought to be true?a. Protons, electrons, and neutrons are evenly distributed throughout the volume of the atom.b. The nucleus is made of protons, electrons, and neutrons.c. Electrons are distributed around the nucleus and occupy almost all the volume of the atom.d. The nucleus is made of electrons and protons.

____ 13. The atomic number of an element is the total number of which particles in the nucleus?a. neutrons c. electronsb. protons d. protons and electrons

____ 14. An element has an atomic number of 76. The number of protons and electrons in a neutral atom of the element are ____.a. 152 protons and 76 electrons c. 38 protons and 38 electronsb. 76 protons and 0 electrons d. 76 protons and 76 electrons

____ 15. The sum of the protons and neutrons in an atom equals the ____.a. atomic number c. atomic massb. nucleus number d. mass number

____ 16. What does the number 84 in the name krypton-84 represent?a. the atomic number c. the sum of the protons and electronsb. the mass number d. twice the number of protons

____ 17. All atoms of the same element have the same ____.a. number of neutrons c. mass numbersb. number of protons d. mass

____ 18. Isotopes of the same element have different ____.a. numbers of neutrons c. numbers of electronsb. numbers of protons d. atomic numbers

____ 19. The mass number of an element is equal to ____.a. the total number of electrons in the nucleusb. the total number of protons and neutrons in the nucleusc. less than twice the atomic numberd. a constant number for the lighter elements

____ 20. Using the periodic table, determine the number of neutrons in O.a. 4 c. 16b. 8 d. 24

____ 21. If E is the symbol for an element, which two of the following symbols represent isotopes of the same element?

1. E 2. E 3. E 4. E

a. 1 and 2 c. 1 and 4b. 3 and 4 d. 2 and 3

____ 22. Which of the following sets of symbols represents isotopes of the same element?a. J J J c. M M M

b. L L L d. Q Q Q

____ 23. Which of the following isotopes has the same number of neutrons as phosphorus-31?a. P c. Si

b. S d. Si

____ 24. Which of the following statements is NOT true?

a. Protons have a positive charge.b. Electrons are negatively charged and have a mass of 1 amu.c. The nucleus of an atom is positively charged.d. Neutrons are located in the nucleus of an atom.

____ 25. The atomic mass of an element is the ____.a. total number of subatomic particles in its nucleusb. weighted average of the masses of the isotopes of the elementc. total mass of the isotopes of the elementd. average of the mass number and the atomic number for the element

____ 26. In the Bohr model of the atom, an electron in an orbit has a fixed ____.a. position c. energyb. color d. size

____ 27. How does the energy of an electron change when the electron moves closer to the nucleus?a. It decreases. c. It stays the same.b. It increases. d. It doubles.

____ 28. When an electron moves from a lower to a higher energy level, the electron ____.a. does not change its energyb. releases energyc. absorbs energyd. moves closer to the nucleus

____ 29. What is the number of electrons in the outermost energy level of an oxygen atom?a. 2 c. 6b. 4 d. 8

____ 30. Emission of light from an atom occurs when an electron ____.a. drops from a higher to a lower energy levelb. jumps from a lower to a higher energy levelc. moves within its atomic orbitald. falls into the nucleus

____ 31. The atomic emission spectra of a sodium atom on Earth and of a sodium atom in the sun would be ____.a. the sameb. different from each otherc. the same as those of several other elementsd. the same as each other only in the ultraviolet range