The Chemical Context of Life Flashcards
what are organisms composed of?
organisms are composed of matter.
what is matter?
matter is anything that takes up space and has mass.
what is matter made of?
matter is made of elements.
what are elements?
elements are substances that cannot be broken down to other substances by chemical reactions.
how many naturally occurring elements are there and how many elements in general?
there are 92 naturally occurring elements and 118 in general.
how many of the naturally occurring elements are essential elements?
20-25% of the naturally occurring elements are essential elements.
what are essential elements?
essential elements are hose that an organism requires in order to remain healthy and reproduce.
what are the main 4 elements needed by the human body?
oxygen, carbon, hydrogen, nitrogen.
what elements make up 96% of living matter?
oxygen, carbon, hydrogen, and nitrogen.
what elements make up the remaining 4% of matter?
calcium, phosphorus, potassium, sulphur, sodium, chlorine, and magnesium.
what are trace elements?
trace elements are only required by the organism in very small amounts.
what are some examples of trace elements?
iron, iodine, copper, boron, chromium, cobalt, fluorine, manganese, selenium, tin, zinc, silicon, molybdenum.
what are the effects of essential element deficiencies?
nitrogen deficiency: nitrogen is essential for plant growth and plays a crucial role in producing chlorophyll. with nitrogen deficiency it can lead to dying and yellowing of crops.
iodine deficiency: goiter (enlarged thyroid gland).
which of the following is not a trace element in the human body? iodine, zinc, iron, calcium, fluorine?
calcium.
what are elements composed of?
an element is composed of small units of matter that still retain the properties of an element. these small units of matter are called atoms.
what are atoms composed of?
small particles called subatomic particles
what are the 3 main subatomic particles?
- neutrons: no electrical charge
- protons: positively charged
- electrons: negatively charged
where are protons and neutrons found?
protons and neutrons are found in the nucleus of an atom.
where are electrons found?
electrons surround the nucleus in a cloud.
the number of electrons an element has can be identified by?
its atomic number.
the number of protons an element has can be identified by?
its atomic number.
how to find the number of neutrons an atom has?
the number of neutrons = mass number - atomic number
what is a compound?
a compound is a substance consisting of two or more elements combined in a fixed ratio. it has characteristics different from those of its elements.
are the electrons of an atom found at the same distance from the nucleus?
no, the electrons are found at varying distances away from the nucleus of an atom. they vary in the amount of energy they possess. the electrons that are further away, have more energy.
what is the chemical behavior of an atom defined by?
the chemical behavior of an atom is defined by its electron configuration and distribution.
how do you determine how many electron shells an element has?
depends on the number of electrons (the atomic number). the first shell has 2 electrons, second shell has 8, third shell has 8.
what would the electron shells of a sodium atom look like if the atomic number is 11.
it would have 3 shells. 2 atoms in the first one, 8 in the second shell, and 1 in the third shell.
what are valence electrons?
valence electrons are the electrons in the outermost electron shell.
what in specific determines the chemical behavior of an atom?
the valence electrons.
what is the valence shell?
the outermost shell is called the valence shell.
what is the valence of an atom?
the valence of an atom is the number of unpaired electrons in its valence shell.
how many valence electrons does na have? what is the valence of na?
1, 1
if the valence shell is full…?
if the valence shell is filed to capacity, the atom is inert/unreactive
if the valence shell isn’t full…?
if the valence shell is not full, it is reactive. it can combine and interact with other atoms it comes into contact with.
