BIOL 235 CHAPTER 2 EXAM QUESTIONS AND
ANSWERS GRADED A+ 100% VERIFIED.
What is a chemical element? ANS >>> It represents the building blocks
of matter (both living and nonliving). It is also a substance that cannot
be split into a simpler substance by ordinary chemical means.
What is a chemical symbol? ANS >>> A one or two letter
representation of a chemical element.
How many chemical elements are? ANS >>> 118
How many elements that occur naturally on Earth? ANS >>> 92
What is a major element? ANS >>> One of four elements that
constitute about 96% of the body's mass
What are the major elements? ANS >>> 4: CHON
,• Carbon
• Hydrogen
• Oxygen
• Nitrogen
What percentage of the body's mass constitute the major elements?
ANS >>> The major elements constitute 96% of the body's mass.
What is a lesser element? ANS >>> One of eight elements that
contribute about 3.6% to the body's mass.
What are the lesser elements? ANS >>> 8: > One
• Phosphorus P
• Calcium Ca
• Sulphur S
• Potassium K
• Sodium Na
• Chlorine Cl
• Magnesium Mg
• Iron Fe
,What percentage of the body's mass constitute the lesser elements?
ANS >>> The lesser elements constitute 3.6% of the body's mass.
What is a trace element? ANS >>> It is one of the 14 elements that are
present in tiny amounts in the body (0.4%)
What are the trace elements? ANS >>> 14: Aluminium (Al), boron (B),
chromium (Cr), cobalt (Co), copper (Cu), fluorine (F), iodine (I),
manganese (Mn), molybdenum (Mo), selenium (Se), silicon (Si), tin (Sn),
vanadium (V), and zinc (Zn).
What percentage of the body's mass constitute the trace elements?
ANS >>> The trace elements constitute 0.4% of the body's mass.
What are atoms? ANS >>> They’re the smallest units of matter that
retain the properties and characteristics of the element
What is a subatomic particle? ANS >>> It is a particle smaller than an
atom.
What subatomic particles are? ANS >>> • protons (p+)
• neutrons (n0)
• electrons (e-)
, What does an atom contain? ANS >>> • nucleus (p+ and n0)
• electrons (e-)
What is a nucleus? ANS >>> It is the central core of an atom; it
contains protons and neutrons.
What is a proton? ANS >>> It is a positively charged particle inside the
nucleus of an atom
What is a neutron? ANS >>> It is an uncharged (neutral) particle inside
the nucleus of an atom.
What is an electron? ANS >>> It is a negatively charged particle that
moves about in a large space surrounding the nucleus.
What are electron shells? ANS >>> They are regions around the
nucleus in which groups of electrons are most likely to move about.
They may be depicted as simple circles around the nucleus.
How many electrons can electron shells hold? ANS >>> • first shell can
hold 2 electrons
• second shell can hold 8 electrons
• third shell can hold 18 electrons
ANSWERS GRADED A+ 100% VERIFIED.
What is a chemical element? ANS >>> It represents the building blocks
of matter (both living and nonliving). It is also a substance that cannot
be split into a simpler substance by ordinary chemical means.
What is a chemical symbol? ANS >>> A one or two letter
representation of a chemical element.
How many chemical elements are? ANS >>> 118
How many elements that occur naturally on Earth? ANS >>> 92
What is a major element? ANS >>> One of four elements that
constitute about 96% of the body's mass
What are the major elements? ANS >>> 4: CHON
,• Carbon
• Hydrogen
• Oxygen
• Nitrogen
What percentage of the body's mass constitute the major elements?
ANS >>> The major elements constitute 96% of the body's mass.
What is a lesser element? ANS >>> One of eight elements that
contribute about 3.6% to the body's mass.
What are the lesser elements? ANS >>> 8: > One
• Phosphorus P
• Calcium Ca
• Sulphur S
• Potassium K
• Sodium Na
• Chlorine Cl
• Magnesium Mg
• Iron Fe
,What percentage of the body's mass constitute the lesser elements?
ANS >>> The lesser elements constitute 3.6% of the body's mass.
What is a trace element? ANS >>> It is one of the 14 elements that are
present in tiny amounts in the body (0.4%)
What are the trace elements? ANS >>> 14: Aluminium (Al), boron (B),
chromium (Cr), cobalt (Co), copper (Cu), fluorine (F), iodine (I),
manganese (Mn), molybdenum (Mo), selenium (Se), silicon (Si), tin (Sn),
vanadium (V), and zinc (Zn).
What percentage of the body's mass constitute the trace elements?
ANS >>> The trace elements constitute 0.4% of the body's mass.
What are atoms? ANS >>> They’re the smallest units of matter that
retain the properties and characteristics of the element
What is a subatomic particle? ANS >>> It is a particle smaller than an
atom.
What subatomic particles are? ANS >>> • protons (p+)
• neutrons (n0)
• electrons (e-)
, What does an atom contain? ANS >>> • nucleus (p+ and n0)
• electrons (e-)
What is a nucleus? ANS >>> It is the central core of an atom; it
contains protons and neutrons.
What is a proton? ANS >>> It is a positively charged particle inside the
nucleus of an atom
What is a neutron? ANS >>> It is an uncharged (neutral) particle inside
the nucleus of an atom.
What is an electron? ANS >>> It is a negatively charged particle that
moves about in a large space surrounding the nucleus.
What are electron shells? ANS >>> They are regions around the
nucleus in which groups of electrons are most likely to move about.
They may be depicted as simple circles around the nucleus.
How many electrons can electron shells hold? ANS >>> • first shell can
hold 2 electrons
• second shell can hold 8 electrons
• third shell can hold 18 electrons
