LO set 2 Flashcards
what types of atoms do covalent bonds form between
non-metal atoms
when is a covalent bond formed?
when two positive nuclei are held together by their common attraction for a
shared pair of electrons
what are the 7 elements that exist as diatomic molecules through the formation of covalent bonds?
H2, N2, F2, O2, I2, Cl2, Br2
what does the shape of simple covalent molecules depend on?
the number of bonds and the orientation of these bonds around the central atom
what 4 terms can be used to describe the shape of simple covalent molecules?
linear, angular, trigonal pyramidal or tetrahedral
what 2 structures can covalent substances form?
discrete molecular or giant network structures
what kind of bonds do covalent molecular substances have?
strong covalent bonds within the molecules and only weak attractions between the molecules
why do covalent molecular substances have low melting and boiling points?
only weak forces of attraction between the molecules are broken when a substance changes state
why don’t covalent molecular substances conduct electricity?
they do not have charged particles which are free to move
what kind of bonds do covalent network structures have?
strong covalent bonds within one giant structure
why do covalent network structures have very high melting and boiling points?
the network of strong covalent bonds is not
easily broken
why do covalent network substances not conduct electricity?
they do not have charged particles which are free to move.
when are ions formed?
when atoms lose or gain electrons to obtain the stable electron arrangement of a noble gas
why do metal atoms lose electrons?
to form positive ions
do non-metal atoms gain or lose electrons when forming negative ions
gain
