Chapter 2 chemistry Flashcards

1
Q

What is an element?

A

Any substance that cannot be broken down to any other substance by chemical reaction.

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2
Q

What are the four elements that make up 96% of living matter?

A

carbon, hydrogen, nitrogen, oxygen

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3
Q

What are trace elements?

A

Elements that are required by organisms in only minute quantities.

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4
Q

What compound accounts for the high percentage of oxygen in the human body?

A

Carbon dioxide (CO2)

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5
Q

What is matter?

A

Anything that takes up space and has mass

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6
Q

What is a compound?

A

A substance consisting of 2 or more different elements combined in a fixed ratio

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7
Q

What are essential elements?

A

Chemical elements required for organisms to survive, grow, and reproduce

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8
Q

What is the atomic nucleus?

A

An atom’s central core containing subatomic particles protons and neutrons

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9
Q

What is Dalton?

A

A measure of mass for atoms and subatomic particles

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10
Q

What is the atomic number?

A

The number of protons in the nucleus

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11
Q

what is mass number?

A

The total number of protons and neutrons

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12
Q

What is atomic mass?

A

The average mass of all isotopes of an element

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13
Q

What are isotopes?

A

One of several atomic forms of an element

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14
Q

What differs between isotopes of an element?

A

Number of neutrons

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15
Q

What is a radioactive isotope?

A

An isotope that is unstable, the nucleus decays spontaneously

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16
Q

What is Half-life?

A

The amount of time it takes for 50% of a sample of a radioactive isotope to decay

17
Q

What is radiometric dating?

A

A method for figuring out the absolute age of rocks and fossils, based on the half-life of radioactive isotopes.

18
Q

What is energy?

A

The capacity to cause change

19
Q

What is potential energy?

A

The energy that matter possesses because of its location or structure

20
Q

What are electron shells?

A

Energy level of electrons with different distances from the nucleus of an atom

21
Q

What are valence electrons?

A

electrons in the outermost shell involved in the chemical reactions of an atom

22
Q

What is the valence shell?

A

The outermost shell of an atom

23
Q

what is an orbital?

A

The 3-dimensional space where an electron is found 90% of the time

24
Q

What are chemical bonds?

A

An attraction between 2 atoms from sharing valence electrons or the presence of opposite charged on the atoms

25
Q

What is a covalent bond?

A

A type of strong chemical bond in which 2 atoms share valence electrons

26
Q

what is a molecule?

A

2 or more atoms held together by covalent bonds

27
Q

what is a single bond

A

a single covalent bond, the sharing of one pair of valence electrons

28
Q

what is a double bond?

A

A double covalent bond, sharing of 2 pairs of valence electrons

29
Q

What is the valence?

A

the bonding capacity of a given atom

30
Q

what is electronegativity?

A

The attraction of a given atom for the electrons of a covalent bond

31
Q

Nonpolar covalent bonds

A

A type of covalent bond where electrons are shared equally between 2 atoms of similar electronegativity

32
Q

polar covalent bonds

A

A type of covalent bond where electronegative differs

33
Q

Ions

A

an stop or group of atoms that has gained or lost one or more electrons thus acquiring a charge

34
Q

cation

A

a positively charged ion

35
Q

Anion

A

A negatively charged ion

36
Q

ionic bond

A

a chemical bond caused by the attraction between oppositely charged ions

37
Q

ionic compounds/salts

A

A compound caused by the formation of an ionic bond

38
Q

chemical reactions

A

the making and breaking of chemical bonds leading to changes in the composition of matter