Chemistry Semester 2 Final Exam Flashcards
Specific patterns in the periodic table that make it possible to make predictions about an element’s properties
periodic trends
As the atomic number increases, the nuclear attraction for electrons increases, thus pulling the electrons in more tightly to the nucleus
Coulomb’s law
One-half the distance between the nuclei of two identical atoms bonded together
atomic radius
A measure of how readily an atom will react
reactivity
When electrons in the inner energy levels block the attraction of the nucleus to the valence electrons
shielding effect
A measure of the ability of an atom in a bond to attract electrons
electronegativity
it is a measure of a neutral atom’s ability to gain an
electron
electron affinity
The energy required to remove one electron from a neutral atom of an element
ionization energy
the charge of an ion
oxidation numbers
The radius of a monatomic ion in an ionic compound
ionic radius
A force/mutual electrical attraction that holds atoms together in a substance
chemical bond
A measure of the ability of an atom in a bond to attract electrons
electronegativity
The tendency of atoms to prefer to have 8 valence electrons
Octet rule
Compound formed when 2 or more elements are covalently bonded
molecule
A binary ionic compound between 1 kind of metal atom and 1 kind of nonmetal atom
salt
Network of cations and anions that are mutually attracted to one another
crystal lattice
A compound made of positive and negative ions that chemically bond in a way that the charges equal out.
ionic compound
charged atoms
ion
Positively charged atom from losing electrons
cation
Negatively charged atom from gaining electrons
anion
A positively or negatively charged, covalently bonded group of atoms
polyatomic ion
Metals that “transition” because they can form many different ions
transition metal
An interaction that holds metal atoms together through a shared pool of valence electrons
metallic bond
Electrons not associated with a single atom or bond
delocalized electron
A solution of two metals mixed together
alloy
A compound formed when two or more atoms share electrons
covalent compound
The bond between nonmetallic atoms that share electrons
covalent bond
A neutral group of atoms held together by covalent bonds
molecule
When 2 atoms of the same element exist naturally as a molecule
diatomic elements
Process by which substances collide with enough energy that new bonds are formed between atoms, thus creating new substances
chemical reaction
starting substances
reactants
ending substances
products
dissolved in water
aqueous
A binary compound with at least 1 atom of oxygen
oxide
A compound made of cations and anions
salt
The decomposition of a substance by an electric current
electrolysis
A compound made of carbon and hydrogen
hydrocarbon
An insoluble solid that forms from the ions of two aqueous compounds
precipitate
A list of elements in the order in which they will easily undergo certain chemical reactions
activity series
Summarize the connection between Coulomb’s law and the periodic trends.
↑ atomic number, ↑ the number of p+
↑ number of p+, ↑ the strength of positive nuclear charge
↑ strength of (+) nuclear charge, ↑ attractive force on e-
This law explains why we see the trends we see in atomic radii, reactivity, electronegativity, etc.
It is all about how tightly the electrons are being held to the nucleus, which is impacted by the # of p+ in the nucleus, and the number of e- 🡪 both the total and specifically in the outermost energy level.
Ionic radii:
Atoms that lose e- become smaller
Atoms that gain e- become larger
Tends to increase as you go DOWN a group
Explain how the shielding effect works.
This occurs when electrons in the inner energy levels block the attraction of the nucleus to the valence e-, and thus they become more loosely held.
It increases as you go down a group as the atomic size is increasing.
Describe how the difference in electronegativity between two atoms can be used to predict the type of bond that could form. Include an example to support your description.
ΔEN shows if one atom will more strongly attract the e- than the other. If the attraction is super strong (ΔEN > 2), an ionic bond forms because one takes the e- from the other. If the attraction is very low (ΔEN < 0.5), a covalent bond forms and the e- are mostly equally shared. If ΔEN is somewhere in the middle, a polar covalent bond is formed where e- are unequally shared.
Ex. Atmospheric nitrogen (N2) makes a ΔEN = 0, thus a covalent bond will form and e- will be equally shared.
Identify the oxidation numbers for elements in groups 1, 2, and 13-17.
Group 1 🡪 +1
Group 2 🡪 +2
Group 13 🡪 +3
Group 14 🡪 +/- 4
Group 15 🡪 -3
Group 16 🡪 -2
Group 17 🡪 -1
Differentiate between the forces between different substances versus the forces within a substance.
Intermolecular forces are between different substances
Intramolecular forces are within the same substances (chemical bonds)
Explain what is meant by the statement, “Bonding is a spectrum.”
There aren’t just two types of bonds. It is a spectrum with ionic and nonpolar covalent at the two extremes.
Write a sentence to summarize the connections between chemical bonds, chemical reactions, and compounds.
Chemical bonds form through chemical reactions and result in new compounds.
Explain why most atoms form chemical bonds and why some atoms don’t.
They form bonds to be stable with full outer energy levels of electrons.
Noble gases don’t form chemical bonds because they are already stable.
Explain the difference between what a chemical formula tells you about an ionic versus a covalent compound.
In a covalent compound, the chemical formula tells you exactly the number and types of atoms.
In an ionic compound, it represents the ratio of cations to anions in the crystal lattice.