BIOLOGY 151 MCPHS (TEST 1) EXAM QUESTIONS AND ANSWERS WITH COMPLETE SOLUTIONS VERIFIED LATEST UPDATE

BIOLOGY 151 MCPHS (TEST 1) EXAM QUESTIONS AND

ANSWERS WITH COMPLETE SOLUTIONS VERIFIED

LATEST UPDATE


Atom


Smallest unit of an element


Element


A unit of matter that cannot be broken down chemically into other substances


Molecule


Two or more atoms held together by a covalent bond


Compound


Two or more elements that chemically combine to make a new substance


Mass of proton


Approx. 1 dalton


Mass of neutron


appox 1 dalton


Mass of electron

, Negligible


Isotope


An atom of a given element with the same atomic number but different mass number


Potential energy of an electron


Is increased as the distance between an electron is from its nucleus


Valence Electrons


The electrons in the outermost shell (main energy level) of an atom; these are the electrons involved in

forming bonds.


Covalent bond


Sharing of a pair of valence electrons by two atoms. Can be polar or non polar.


Polar


Having a pair of equal and opposite charges.


Nonpolar


Equal sharing of electrons


Example of Covalent bond


Methane: (CH4). Non-polar

Water: (H20) Polar.


Ionic Bonds


Formed due to the attraction between oppositely charged ions (cations and anions)