NAME:_______________________________
Unit 3 HOMEWORK PACKET 4
DATE:___________
AHS Instructor Ms. Kasia Room 109
3.3 What are the subatomic particles?
1. According to the wave-mechanical model of the atom, electrons in an
atom
a. travel in defined circles
b. are most likely found in an excited state
c. have a positive charge
d. are located in orbitals outside the nucleus
Explain how you arrived at your answer
2. Which two particles each have a mass approximately equal to one
atomic mass unit
a. Electron and neutron
b. Electron and positron
c. Proton and electron
d. Proton and neutron
Explain how you arrived at your answer
3. Which subatomic particles are located in the nucleus of a neon atom?
4. Which phrase describes an atom?
e. A positively charged electron cloud surrounding a positively charged
nucleus
f. A positively charged electron cloud surrounding a negatively charged
nucleus
g. A negatively charged electron cloud surrounding a positively charged
nucleus
h. A negatively charged electron cloud surrounding a negatively charged
nucleus
Explain how you arrived at your answer
3.4 What is the atomic number and how can I use it to calculate the mass of an atom?
1. Which statement identifies the element arsenic?
a. Arsenic has an atomic number of 33
b. Arsenic has a melting point of 84K
c. An atom of arsenic is the ground state has eight valance electrons
d. An atom of arsenic in the ground state has a radius of 146pm
Explain how you arrived at your answer
2. An atom is electrically neutral because the
a. number of protons equals the number of electrons
b. number of protons equals the number of neutrons
c. ratio of the number of neutrons to the number of electrons is 1:1
d. ratio of the number of neutrons to the number of protons is 2:1
Explain how you arrived at your answer
3. What is the charge of the nucleus of a nitrogen atom
a. -7
b. 0
c. +7
d. 14
Explain how you arrived at your answer
4. What is the charge on a particle that contains 9 protons, 10 neutrons, and
9 electrons?:
a. it is neutral
b. it has a net charge of 1+
c. it has a net charge of 1d. it has a net charge of 28+
Explain how you arrived at your answer
5. If the atomic number of a neutral element is 35, and its nucleus contains
40 neutrons, which of the following is correct?
a. the atom is bromine and it has 35 electrons
b. the atoms is bromine and it has a mass number of 40
c. the atom is zirconium and it has a mass number of 75
d. the atom is zirconium and it has 40 electrons
Explain how you arrived at your answer
3.5 What is an isotope?
3.6 Average Atomic Mass
1. A scientist traveled to Jupiter and
discovered that the oxygen on that
planet is 74% 18O, 5% 17O, and 11%
16
O. Calculate the average atomic
mass for oxygen on Jupiter. Show all
work.
Show your work
3.7 What is Electron Configuration?
1. Draw a planetary model for an atom of the following elements:
Arsenic
Barium
Manganese
2. Given Samples of Na, Ar, As, and Rb, which two elements have the
most similar chemical properties?
Explain how you arrived at your answer
3. What is the total number of valance electrons in an atom of Mg-26 in
the ground state?
Explain how you arrived at your answer