Chemistry Unit 2 Test: The Atom Flashcards
the smallest unit of an element that still has the properties of that element
atom
the positive subatomic particle in the nucleus of an atom
proton
the neutral subatomic particle in the nucleus of an atom
neutron
the negative subatomic particle in the electron cloud of an atom
electron
electrons in the outermost energy level of the electron cloud
valence electrons
make up protons and neutrons and their attraction holds the nucleus together
quarks
the atom is positively charged with negatively charged particles embedded throughout
plum pudding model
the center of the atom (nucleus) is positive and the negative parts surrounds it
nuclear model
the plum pudding model represents
an important step in the development in atomic theory; not only did it incorporate new discoveries, such as the existence of the electron, it also introduced the notion of the atom as a non-inert, divisible mass
the nuclear model was
the first step toward our modern understanding of the atom
e- (electrons) travel in fixed orbits around the nucleus
Bohr model
e- (electron) are in shells in the cloud but do NOT travel in fixed orbits
Electron cloud model
Be able to differentiate between the Plum Pudding Model and the __________________
Nuclear Model
Be able to differentiate between the Bohr Model and the _________________
Electron Cloud Model
Explain the structure of the electron cloud: (3 points)
1) Divided into shells/energy levels
2) Electrons in the shell closest to the nucleus have the least amount of energy (holds a max of 2 electrons)
3) Electrons in the shell farthest from the nucleus have the most energy (and these outermost electrons are called valence electrons)
Describe the forces that hold the atom together: (2 points)
1) There is an attractive electromagnetic force between the positive nucleus and the negative electron cloud.
2) There is also the strong nuclear force between the quarks in the nucleus that holds it together despite the repulsive electromagnetic force between the positive protons.
number of protons in an atom of the element; used to identify an element
atomic number
number of protons and neutrons in the nucleus of an atom
mass number
AKA families
groups
the vertical columns on the periodic table
groups
Groups have what in common?
number of valence electrons
Periods have what in common?
energy levels
the horizontal rows on the periodic table
periods
atoms of the same elements with different numbers of neutrons
isotopes
a charged atom
ion
weighted average of all of the different versions of an element; measured in amu
average atomic mass
described the pattern/shared characteristics that elements in the same group share versus elements in the same period
Elements in the same group have the same number of valence electrons.
Elements in the same period have the same number of energy levels in their electron clouds.
Explain why elements in the same group often have similar properties. Then list any names and special characteristics that define these groups.
Elements in the same group often have similar properties because they have the same number of valence electrons and thus, have similar bonding patterns.
Group 1 on the periodic table:
Alkali metals - most reactive metals
Group 2 on the periodic table:
Alkaline earth metals
Group 3 on the periodic table:
rare earth metals
Groups 3-12 on the periodic table:
Transition metals
Group 17 on the periodic table:
Halogens - most reactive nonmetals
Group 18 on the periodic table:
Noble gases - nonreactive
Which group contains the most reactive metals and what are they called?
Group 1, Alkali metals
Which group contains the most reactive nonmetals and what are they called?
Group 17, Halogens
Which group contains the least reactive and why?
Group 18 - this is because they have a full valence electron shell, making them chemically stable
Metals:
left of metalloids, usually solids, good conductors
Nonmetals:
right of metalloids, (except Hydrogen), usually gases or dull and brittle solids, poor conductors
Metalloids:
B, Si, Ge, As, Sb, Te, solids, semi-conductors, physical properties like metals chemical properties like nonmetals
Give an example of hyphen and nuclear notation for the most common isotope of Hydrogen. Explain what the notation tells you about the atom.
Hydrogen - 1
1(subscript)H
The notation tells you the identity of the atom and its mass number. It can also notate if the atom has a charge or is electrically neutral.
Explain what it means for an atom to be electrically neutral, and include the name for an atom that is NOT electrically neutral.
An electrically neutral atom has an equal amount of positive protons and negative electrons, and therefore has an overall charge of 0.
An atom that is NOT electrically neutral has an imbalance of p+ and e- and thus has a charge. This is known as an ion.
