Module 1 (Chemistry of Life) Flashcards
Life’s chemical backbone
Carbon
What are valence electrons?
- the number of electrons on the outermost shell
Why are valence electrons important?
Valence electrons and electron orbitals define the chemical reactivity of a substance
Versions of an element with different neutrons and mass numbers
Isotopes
Unstable isotopes that give off energy in the form of radiation that comes from the nucleus
Radioisotopes
Two protons and two neutrons (helium nuclei), positively charged
http://tinyurl.com/3p26k9d2
Alpha radiation
A beta particle (highly energetic electron) is released, negatively charged
http://tinyurl.com/3zyhh23p
Beta radiation
Highly energetic photons, short wavelength, electromagnetic, radiation is neutral. Usually accompanies an alpha or beta particle
http://tinyurl.com/2dua2h8r
Gamma radiation
True or False: Biologically, the total number of electrons of a chemical element are what determines the chemical element’s reactivity
False
It’s the valence electrons that determine the chemical element’s reactivity, not the total number of electrons
Transforms the atom, changes the number of neutrons
Radiation decay (alpha, beta, and gamma)
The number of bonds an atom can form is determined by
The number of unpaired valence electrons
Carbon can form how many covalent bonds?
4 covalent bonds
Oxygen can form how many covalent bonds?
2 covalent bonds
Nitrogen can form how many covalent bonds?
3 covalent bonds
Equal sharing of electrons, atoms have no charge
Nonpolar covalent bond
Atoms have partial charge, sharing of the electrons is not evenly divided
Polar covalent charge
Atoms have full charge, there is a transfer of electrons
Ionic bonds
Chemical property that describes the tendencies of an atom to attract electrons towards itself
Electronegativity
Which has more electronegativity, hydrogen or oxygen?
Oxygen
Nonpolar value scale
0 - 0.4
Polar threshold
0.4 - 0.5
Polar value scale
0.5 - 1.8
Ionic value scale
1.8 +
In water, is the partial positive charge near the oxygen or the hydrogens?
The hydrogens
In water, is the partial negative charge near the oxygen or the hydrogens?
The oxygen
In a hydrophobic environment, how do water molecules behave?
Water molecules hydrogen bond to other water molecules (H - O)
What elements does hydrogen connect to to create hydrogen bonding?
Fluorine, oxygen, or nitrogen
Warmer temperatures for water molecules causes more ______ (less proximity) between them, therefore there is _____ hydrogen bonding
dispersion, less
Why is it important that water is a solvent for charged/polar compounds?
Most chemical reactions important for life take place in aqueous solution
True or False: Water is denser as a liquid than a solid
True
True or False: water has high specific heat and a high heat of vaporation
True
NaCl is able to dissolve in water because
They are both polar substances
Glucose is unable to dissolve in water because
Glucose is a nonpolar molecule and water is a polar molecule. Since they have different polarities, they don’t mix
When NaCl and water mix, it creates a _______ __ _____, where the oxygen surrounds the sodium and the hydrogen surrounds the chlorine
Sphere of hydration
Which is more likely to form a chemical bond with another atom: carbon or argon?
Carbon, because argon already has a full shell according to the octet rule
What is the bond between two oxygens called?
Nonpolar
The less polar bonds, the more ______ the molecule is
Hydrophobic
If a molecule has about the same number of polar and nonpolar bonds, the molecule will be _____, and will be able to _____ ______ with water
Polar, hydrogen bond
When molecules are surrounded by water molecules, but sticking to itself, this type of molecule is _____
Hydrophobic
When a molecule is surrounded by water molecules on all sides and isn’t sticking to itself, this type of molecule is
Hydrophilic
Atoms stick together for a long period of time, atoms have similar characteristics
Molecular Complementarity
Interactions can result in _______ tendencies, where they stick together to avoid water (form of molecular complementarity)
Hydrophobic
Two molecules, one with a positive charge and the other with a negative charge, have _____ molecular complementarity
Strong
Two molecules, both with negative charges, have _____ molecular complementarity
Weak
In a protein, there can be _____ _____ of molecular complementarity occurring
Different types
