Chapter 2- Chemical Basis Of Life Flashcards Preview

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Flashcards in Chapter 2- Chemical Basis Of Life Deck (104)
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Electricity

The flow of electrons (energy)

1

Matter

Anything that takes up space and has mass

2

Mass

A measure of the amount of matter an object contains

****Stays the same regardless if changes in the objects position****

3

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

5

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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Valence

Bonding capacity of an atom which is the number of covalent bonds that must be formed to complete the outer shell