Flashcards in Chapter 2- Chemical Basis Of Life Deck (104)
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Electricity
The flow of electrons (energy)
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Matter
Anything that takes up space and has mass
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Mass
A measure of the amount of matter an object contains
****Stays the same regardless if changes in the objects position****
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Weight
The measure of how strongly an object is pulled by earths gravity and it varies with distance from earths center
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Trace elements
Elements required by life in very minute quantities
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Ultratrace elements
Element required by organisms in extremely minute quantities but are TOXIC at high levels (arsenic- Ar)
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Compound
A pure substance composed of 2+ different elements combined in a fixed ratio (✔️molecule)
Ex: NaCl (sodium chloride)
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Molecule
2+ atoms
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Atom
Smallest possible unit of matter that retains chemical/physical properties of its element
Atoms of the same element share similar chemical properties
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Subatomic particles
Neutrons, Protons, electrons
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Electrostatic charge
✔️Two opposites attract each other
✔️Positive attracts negative
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What is unique about hydrogen
It has only one electron and one proton, NO neutrons
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Atomic nucleus
Where protons and neutrons are found; where mass of entire atoms is measured
Mass of 1 proton, one neutron= 1 Dalton
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Where are electrons located
Orbit around the nucleus; held together by electrostatic attraction to positively charged nucleus
Mass so small, it's not used to calculate atomic mass
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Atomic number
DETERMINES the atom (unique to each)
Number of protons in an atom
All atoms of an element have the same atomic number (subscripts to the of the elements written symbol)
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Mass number
Number of protons and neutrons in an atom (one of each has mass of approx 1 dalton)
Superscript to left or an elements symbol
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Octet rule
1st shell- max 2 electrons
2nd shell- max 8 electrons
3rd shell- max 8 electrons
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In what shell do electrons have most energy
The further out the shell, the more energy the electrons have because they aren't being pulled into positively charged nucleus as strongly
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Chemical reactions always go to the _________________? energy state
Chemical reactions always go to the LOWEST energy state
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Inert
NOT reactive
Outermost shell is naturally full; ALL gasses (noble gasses)
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Isotopes
Atoms of an element that have the same atomic number but different mass number
Different number of NEUTRONS
Under natural conditions, elements occur as mixtures of isotopes
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Different isotopes of the same element react chemically in the ____________ way.
Different isotopes of the same element react chemically in the SAME way.
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Radioactive isotope
Unstable isotope in which the nucleus spontaneously decays emitting subatomic particles and/or energy as radioactivity
Fixed half-life
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What are two biological applications of radioactive isotopes
1. Dating geological strata (layers) and fossils
2. Radioactive tracers
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Radioactive tracers
Trace steps of biochemical reaction or to determine the location of a particular substance within organism
Useful bc they chemically react like the stable isotopes and are easily detected at low concentrations
Diagnose disease
Cause or cure cancer
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Octet rule
Rule that valence shell is complete when it contains 8 electrons
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Chemical bond
Attractions that hold molecules together
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Covalent bond
✔️Strongest bond
✔️Chemical bonds formed by sharing s pair of valence electrons
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Carbon and silicon have 4 valence electrons, what is this called?
Tetravalent
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