Microscopic world 2 Flashcards
(19 cards)
why some molecules are in trigonal pyramidal
repulsion between electron pairs
why radicals have high reactivity
it doesn’t have stable octet
why water will deflect towards charged rod
water is a polar molecule
explain the formation of hydrogen bonding in hydrogen fluoride
N/O/F is a highly electronegative element
H-F/H-O/H-N covalent bond is very polar
why ethyl ethanoate is a better solvent than water for dissolving cinnamaldehyde.
cinnamaldehyde is a non-polar compound that can dissolve in a relatively non-polar organic solvent like ethyl ethanoate. However, water is a polar solvent.
Explain why the density of ice is lower than that of water
The attraction between water molecules is predominately hydrogen bond
Hydrogen bond is directional. In ice, the water molecules have a tetrahedral arrangement and packed in an open structure.
In liquid water, the water molecules have relative motions and this leads to the collapse of the open structure. The molecules become more closely packed. So liquid water has higher density than ice.
VSEPR theory states that
the theory is out syl but better rmb it also :)
electron pairs in the outermost shell of the central atom in a molecule will stay as far as possible
BeCl2 shape?
linear
its a covalent molecule
meaning of octet rule
all atoms tend to achieve the stable electronic arrangement of a noble gas by sharing or transferring electrons
definition of dative covalent bond
it is a covalent bond in which both electrons in the bond are donated by one atom
definition of electronegativity
the ability of an atom to attract bonding electrons in a covalent bond
electronegativity sequence for common atoms
F>O>N~Cl>Br>C>H~P
trend of atomic size through a period
more outermost electrons
small atomic size in the same period
hydrogen bond definition
its a strong intermolecular force between a H atom covalently bonded to a small highly electronegative atom in one molecule and the lone pair electrons on a small highly electronegative atom in another molecule
what is viscosity
the resistance of a liquid to flow
depends on intermolecular force
what is crystal
it is a solid material whose constituent atoms/molecules are arranged in an orderly repeating pattern extending throughout the material including metallic crystal ionic crystal covalent crystal molecular crystals
why ice is less dense than water
the intermolecular attraction in both ice and liquid water is mainly hydrogen bond
In solid ice, each H2O molecule is surrounded by four other H2O molecules tetrahedrally, this results in a regular open network structure.
when ice melts, the open structure collapse. Molecules can be packed closely together in liquid water than in ice,
Therefore, ice has a smaller density than water.
what is allotropes
allotropes are different structural form of the same element
total number of lone pair electrons in a PCl3 molecule is 10
T/F
T
(scl mock)
inner shell dont need to be calculated
