Ch 2 The Chemical Context of Life Flashcards
(27 cards)
Atoms are defined by their number of ___
Protons
The atomic mass is the number of ___ plus ___
Protons + Neutrons
Atomic number is the number of
Protons
and electrons when neutral
Atoms that differ only in number of neutrons
Isotopes
Something that is :
- Unstable
- Spontaneously emit particles and energy
- Can be useful in research and medicine
Radioactive Isotopes
Position of electron determines its ____
Potential energy
Electron shells that are farther from the nucleus _____
Increase in energy
First electron shell holds ___ electrons
2
Second and third electron shells hold ___ electrons each.
8
Outer most electron shell is the ____
Valence Shell
Electrons in outer most shell are ____
Valence electrons
Covalent bonding results from the _________ of electrons between atoms
sharing
Strongest type of bond in biological setting is ___
Covalent bond
Define electronegativity
the relative attraction of an atom for electrons
High electronegativity = _____
High attraction for electrons
Electronegative atoms, most to least.
Oxygen, Nitrogen, Carbon = Hydrogen
Polar Bond
Bond between atoms with different electronegativities
Non-Polar Bond
Bond between atoms with similar electronegativities
Ionic Bonding results from the ___ of electrons from one atom to another
Transfer
Ionic bonding results in the formation of ____ , charged atoms or molecules.
Ions
Cation
Positive charge
Anion
Negative charge
Ionic interactions
Are ionic bonds in water
2 Requirements for a Hydrogen bond:
- Hydrogen covalently bonded to a an electronegative atom (O or N)
- Another electronegative atom (O or N)
