Vocabulary
What is the center of an atom that contains protons and neutrons and is surrounded by an electron cloud?
Nucleus
Lithium-6 accounts for 7.59% of all naturally occurring lithium atoms. Li-7 accounts for 92.41% of lithium atoms. What is the atomic weight of lithium in amu? Remember Neutrons times Percent + Neutrons times Percent + Atomic Weight.
(6 × 0.0759) + (7 × 0.9241) = 6.924 amu
The nucleus of an atom contains what two things?
Protons and Neutrons
What does Cl stand for on the Periodic Table?
Chlorine
What is the number of protons in one atom of an element ?
Atomic Number
What is the sum of the number of protons and neutrons in an atom’s nucleus?
Mass number
How did Rutherford determine that most of an atom was empty space?
Rutherford conducted an experiment where he aimed a beam of high-speed, positively charged particles at an extremely thin sheet of gold foil. Many particles traveled straight through, but some of the particles were deflected and a few bounced straight back. Because a majority of the particles passed straight through the foil, Rutherford concluded that most of the atom was empty space.
A neutral atom contains 17 protons, 17 electrons, and 18 neutrons. What is the atomic mass?
35
A neutral potassium atom has an atomic number of 19 and a mass number of 39. How many neutrons does potassium have?
20
What is a Horizontal row of elements in the periodic table?
A Period
What is a negatively charged subatomic particle outside the nucleus of an atom
Electron
Who discovered the neutron?
James Chadwick
True or false. A neutral atom contains more protons than electrons. If False Why?
False. A neutral atom contains equal amounts of protons and electrons.
True or False: Noble gases are highly reactive because they have seven valence electrons. If False Then Why?
False. Noble gases are unreactive because they have eight valence electrons.
What is a Proton?
A positively charged subatomic particle in the nucleus of every atom.
What is a vertical column of elements in the periodic table?
Group
True or False: Mendeleev arranged the periodic table according to atomic mass. If False Why.
True
Explain how the number of valence electrons determines the reactivity of an atom.
Valence electrons determine how atoms react. Each atom seeks the most stable structure possible, which is a full shell consisting of eight electrons. If an atom has very few valence electrons or a shell that is almost complete, it will tend to be more reactive. Elements in Groups I, II, and VII are the most reactive. Incomplete shells create very energetically unfavorable environments. Atoms with a full valence shell are not reactive.
Carbon belongs to what group on the periodic table?
Group IVA
Give an example of how to write out an Isotope?
CL-45 - Stands For Chlorine - 45
What is an element that is usually soft, not malleable or ductile, and a poor conductor of heat and electricity
Nonmetal
True or False: Electrons can exist between orbits according to Bohr’s atomic shell model If False Why
False. Electrons travel around the nucleus in specific orbits or shells according to Bohr’s atomic shell model. They cannot reside between orbits.
Draw an atom of oxygen to include all electrons in increasing energy levels.
Teacher decides
How many protons, neutrons, and electrons does Kr - 84 have?
protons = 36, electrons = 36, neutrons = 48
What is a Valence Electron?
The outermost electrons in a atomic energy level