NAS 2 Chemistry exam with correct solutions
Potential |energy |- |correct |answer |-is |energy |possessed |by |a |body |by |virtue |of |its |position |relative
|to |others, |stresses |within |itself, |electric, |and |other |factors
Kinetic |energy |- |correct |answer |-is |the |energy |that |a |body |possesses |by |virtue |of |being |in |motion
An |atom |- |correct |answer |-is |the |smallest |quantity |of |an |element |that |retains |the |unique
|properties |of |the |element. |atoms |are |made |up |of |even |smaller |subatomic |particles, |protons |(+),
|neutrons |(neutral), |and |electrons |(-)
How |to |find |mass |- |correct |answer |-protons |+ |neutrons |= |mass |, |the |number |of |positively-charged
|protons |and |non-charged |("neutral") |neutrons, |gives |mass |to |the |atoms, |and |the |number |of |each
|in |the |nucleus |of |the |atom |determined |the |element
Number |of |protons |- |correct |answer |-the |number |of |negatively-charged |electrons |that |"spin"
|around |the |nucleus |at |close |to |the |speed |of |light |equals |the |number |of |protons
Mass |of |electron |- |correct |answer |-an |electron |has |about |1/2000th |the |mass |of |proton |or |neutron
Relative |mass/atomic |mass |- |correct |answer |-is |a |dimensionless |(number |only) |physical |quantity. |In
|its |modern |definition, |it |is |the |ratio |of |the |average |mass |of |atom |of |an |element |(in |a |given
|sample) |to |one |unified |atomic |mass |unit
Location |of |proton, |neutrons |and |electrons |- |correct |answer |-electrons |are |on |the |outer |level |of |the
|atom, |the |nucleus |is |in |the |center |of |the |atom |and |the |protons |are |around |the |nucleus
Atomic |number |- |correct |answer |-is |the |number |of |protons |in |the |nucleus |of |the |atom, |identifies
|the |element. |because |an |atom |usually |has |the |same |number |of |electrons |as |protons, |the |atomic
|number |identifies |the |usual |number |of |electron |as |well
Atomic |symbol |- |correct |answer |-is |the |abbreviation |for |the |element, |Carbon |=C
, Atomic |mass |- |correct |answer |-is |the |weight |of |an |atom, |Chlorines |weight |is |35.45
Ion |- |correct |answer |-is |an |atom |or |molecule |with |a |net |electric |charge |due |to |the |loss |or |gain |of
|one |or |more |electrons
Isotope |- |correct |answer |-is |one |of |the |different |forms |of |an |element, |distinguished |from |one
|another |by |different |number |of |neutrons.
Valence |shell |- |correct |answer |-is |an |atoms |outermost |electron |shell. |If |the |valence |shell |is |full, |the
|atom |is |stable; |meaning |its |electrons |are |unlikely |to |be |pulled |away |from |the |nucleus |by |the
|electrical |charge |of |the |other |atoms. |If |the |valence |shell |is |not |all, |the |atom |is |reactive' |meaning |it
|will |tend |to |react |with |other |atoms |in |ways |that |make |the |valence |shell |full
How |to |draw |an |electron |shell |diagram |- |correct |answer |-you |have |to |work |out |which |period |(row)
|it |is |in |and |draw |that |number |of |circles |around |the |nucleus. |Work |out |which |group |the |element |is
|in |and |draw |that |number |of |electrons |in |the |outer |circle |- |with |eight |for |group |0 |elements |- |except
|helium. |Fill |the |other |circles |with |as |many |electrons |as |needed
Covalent |bonds |- |correct |answer |-share |electrons |in |a |mutually |stabilizing |relationship. |the |atoms
|do |not |lose |or |gain |electrons |permanently. |Instead, |the |electrons |move |back |and |forth |between
|the |elements. |Because |of |the |close |sharing |of |pairs |of |electrons |(one |electron |from |each |of |two
|atoms), |covalent |bonds |are |stronger |than |ionic |bonds. |Nonmetal |- |nonmetal
Polar |covalent |- |correct |answer |-is |a |type |of |chemical |bond |where |a |pair |of |electrons |is |unequally
|shared |between |two |atoms. |A |polar |molecule |is |a |molecule |that |contain |regions |that |have
|opposite |charges. |Polar |molecules |occur |when |atoms |share |electron |unequally, |in |polar |covalent
|bonds. |EX |water
Hydrogen |bond |- |correct |answer |-is |formed |when |a |weakly |positive |hydrogen |atom |bonded |to |one
|electronegative |atom |(EX, |the |oxygen |in |the |water |molecule) |is |attracted |to |another
|electronegative |atom |from |another |molecule. |In |other |word, |hydrogen |bonds |always |include
|hydrogen |that |is |already |of |a |polar |molecule
Potential |energy |- |correct |answer |-is |energy |possessed |by |a |body |by |virtue |of |its |position |relative
|to |others, |stresses |within |itself, |electric, |and |other |factors
Kinetic |energy |- |correct |answer |-is |the |energy |that |a |body |possesses |by |virtue |of |being |in |motion
An |atom |- |correct |answer |-is |the |smallest |quantity |of |an |element |that |retains |the |unique
|properties |of |the |element. |atoms |are |made |up |of |even |smaller |subatomic |particles, |protons |(+),
|neutrons |(neutral), |and |electrons |(-)
How |to |find |mass |- |correct |answer |-protons |+ |neutrons |= |mass |, |the |number |of |positively-charged
|protons |and |non-charged |("neutral") |neutrons, |gives |mass |to |the |atoms, |and |the |number |of |each
|in |the |nucleus |of |the |atom |determined |the |element
Number |of |protons |- |correct |answer |-the |number |of |negatively-charged |electrons |that |"spin"
|around |the |nucleus |at |close |to |the |speed |of |light |equals |the |number |of |protons
Mass |of |electron |- |correct |answer |-an |electron |has |about |1/2000th |the |mass |of |proton |or |neutron
Relative |mass/atomic |mass |- |correct |answer |-is |a |dimensionless |(number |only) |physical |quantity. |In
|its |modern |definition, |it |is |the |ratio |of |the |average |mass |of |atom |of |an |element |(in |a |given
|sample) |to |one |unified |atomic |mass |unit
Location |of |proton, |neutrons |and |electrons |- |correct |answer |-electrons |are |on |the |outer |level |of |the
|atom, |the |nucleus |is |in |the |center |of |the |atom |and |the |protons |are |around |the |nucleus
Atomic |number |- |correct |answer |-is |the |number |of |protons |in |the |nucleus |of |the |atom, |identifies
|the |element. |because |an |atom |usually |has |the |same |number |of |electrons |as |protons, |the |atomic
|number |identifies |the |usual |number |of |electron |as |well
Atomic |symbol |- |correct |answer |-is |the |abbreviation |for |the |element, |Carbon |=C
, Atomic |mass |- |correct |answer |-is |the |weight |of |an |atom, |Chlorines |weight |is |35.45
Ion |- |correct |answer |-is |an |atom |or |molecule |with |a |net |electric |charge |due |to |the |loss |or |gain |of
|one |or |more |electrons
Isotope |- |correct |answer |-is |one |of |the |different |forms |of |an |element, |distinguished |from |one
|another |by |different |number |of |neutrons.
Valence |shell |- |correct |answer |-is |an |atoms |outermost |electron |shell. |If |the |valence |shell |is |full, |the
|atom |is |stable; |meaning |its |electrons |are |unlikely |to |be |pulled |away |from |the |nucleus |by |the
|electrical |charge |of |the |other |atoms. |If |the |valence |shell |is |not |all, |the |atom |is |reactive' |meaning |it
|will |tend |to |react |with |other |atoms |in |ways |that |make |the |valence |shell |full
How |to |draw |an |electron |shell |diagram |- |correct |answer |-you |have |to |work |out |which |period |(row)
|it |is |in |and |draw |that |number |of |circles |around |the |nucleus. |Work |out |which |group |the |element |is
|in |and |draw |that |number |of |electrons |in |the |outer |circle |- |with |eight |for |group |0 |elements |- |except
|helium. |Fill |the |other |circles |with |as |many |electrons |as |needed
Covalent |bonds |- |correct |answer |-share |electrons |in |a |mutually |stabilizing |relationship. |the |atoms
|do |not |lose |or |gain |electrons |permanently. |Instead, |the |electrons |move |back |and |forth |between
|the |elements. |Because |of |the |close |sharing |of |pairs |of |electrons |(one |electron |from |each |of |two
|atoms), |covalent |bonds |are |stronger |than |ionic |bonds. |Nonmetal |- |nonmetal
Polar |covalent |- |correct |answer |-is |a |type |of |chemical |bond |where |a |pair |of |electrons |is |unequally
|shared |between |two |atoms. |A |polar |molecule |is |a |molecule |that |contain |regions |that |have
|opposite |charges. |Polar |molecules |occur |when |atoms |share |electron |unequally, |in |polar |covalent
|bonds. |EX |water
Hydrogen |bond |- |correct |answer |-is |formed |when |a |weakly |positive |hydrogen |atom |bonded |to |one
|electronegative |atom |(EX, |the |oxygen |in |the |water |molecule) |is |attracted |to |another
|electronegative |atom |from |another |molecule. |In |other |word, |hydrogen |bonds |always |include
|hydrogen |that |is |already |of |a |polar |molecule
