Topic 2 Flashcards
What is an Ionic Bond?
The strong electrostatic force of attraction between oppositely charged ions formed by electron transfer.
How do metal atoms and non-metal atoms behave in ionic bonding?
Metal atoms lose electrons to form +ve ions; non-metal atoms gain electrons to form -ve ions.
What causes ionic bonding to be stronger with higher melting points?
Ionic bonding is stronger and the melting points higher when the ions are smaller and/or have higher charges.
What is the electron configuration change for Mg in ionic bonding?
Mg goes from 1s2 2s2 2p6 3s2 to Mg2+ 1s2 2s2 2p6.
What is the electron configuration change for O in ionic bonding?
O goes from 1s2 2s2 2p4 to O2- 1s2 2s2 2p6.
What is the trend in ionic radius for positive ions?
Positive ions are smaller compared to their atoms due to having one less shell of electrons.
What happens to the ionic radius of negative ions compared to their atoms?
Negative ions are larger than the corresponding atoms due to having more electrons than protons.
What happens to ionic radii as you move down a group?
The size of the ionic radii increases going down the group due to more shells of electrons.
What is a covalent bond?
A covalent bond is caused by the electrostatic attraction between the bonding shared pair of electrons and the two nuclei.
Why do giant atomic structures like diamond and graphite have high melting points?
They contain many strong covalent bonds in a macromolecular structure, requiring a lot of energy to break.
What effect do multiple bonds have on bond strength and length?
Nuclei joined by multiple bonds have greater electron density, resulting in shorter bond lengths and greater bond strength.
What is the bond angle in a linear molecule?
180 degrees.
What is the bond angle in a tetrahedral molecule?
109.5 degrees.
What is electronegativity?
Electronegativity is the relative tendency of an atom in a covalent bond to attract electrons to itself.
Which elements are the most electronegative?
F, O, N, and Cl.
What is the trend in electronegativity across a period?
Electronegativity increases across a period as the number of protons increases and atomic radius decreases.
What is a polar covalent bond?
A polar covalent bond forms when the elements in the bond have different electronegativities, creating a charge separation.
What determines if a molecule is polar or non-polar?
A symmetric molecule will not be polar even if individual bonds within the molecule are polar.
What happens to a jet of liquid when a charged rod is brought close to it?
A polar liquid will be attracted to the charged rod, aligning its dipoles, while non-polar liquids will not be deflected.
What are London Forces?
London Forces are instantaneous, induced dipole-dipole interactions occurring between all molecular substances and noble gases.
What affects the size of London Forces?
The more electrons in the molecule, the higher the chance for temporary dipoles to form, making London forces stronger.
What are permanent dipole-dipole forces?
Permanent dipole-dipole forces occur between polar molecules and are stronger than London forces.
What is hydrogen bonding?
Hydrogen bonding occurs in compounds with hydrogen attached to nitrogen, oxygen, or fluorine, which have available lone pairs.
Why do water, ammonia, and hydrogen fluoride have high boiling points?
Their anomalously high boiling points are due to hydrogen bonding in addition to London forces.
