Vocabulary - Ch. 4 The Chemical Basis of Life
Write each of the definitions out and leave space to write a sentence later.
1. matter
2. element
3. trace element
4. compound
5. atom
6. proton
7. electron
8. neutron
9. nucleus
10. atomic number
11. isotope
12. radioactive isotope
13. ionic bond
14. ion
15. covalent bond
16. molecule
17. chemical reaction
18. reactant
19. product
20. polar molecule
21. hydrogen bond
22. cohesion
23. adhesion
24. thermal energy
25. temperature
26. solution
27. solvent
28. solute
29. aqueous solution
30. acid
31. base
32. pH scale
33. buffer
Vocabulary - Ch. 4 The Chemical Basis of Life
Write each of the definitions out and leave space to write a sentence later.
1. matter
2. element
3. trace element
4. compound
5. atom
6. proton
7. electron
8. neutron
9. nucleus
10. atomic number
11. isotope
12. radioactive isotope
13. ionic bond
14. ion
15. covalent bond
16. molecule
17. chemical reaction
18. reactant
19. product
20. polar molecule
21. hydrogen bond
22. cohesion
23. adhesion
24. thermal energy
25. temperature
26. solution
27. solvent
28. solute
29. aqueous solution
30. acid
31. base
32. pH scale
33. buffer
Vocabulary - Ch. 4 The Chemical Basis of Life
1. matter- anything that occupies space and has mass (Concept 4.1)
2. element- pure substance that cannot be broken down into other substances by chemical or physical
means (Concept 4.1)
3. trace element- element critical to health that makes up less than 0.01 percent of body mass
(Concept 4.1)
4. compound- substance containing two or more elements chemically combined in a fixed ratio
(Concept 4.1)
5. atom- smallest particle of an element (Concept 4.2)
6. proton- subatomic particle with a single unit of positive electric charge (+) (Concept 4.2)
7. electron- subatomic particle with a single unit of negative electric charge (-) (Concept 4.2)
8. neutron- subatomic particle that has no charge (is electrically neutral) (Concept 4.2)
9. nucleus- in an atom, the central core that contains protons and neutrons (Concept 4.2);
10. atomic number- number of protons in an atom's nucleus; is unique for each element (Concept 4.2)
11. isotope- one of several forms of an element, each containing the same number of protons in their
atoms but a different number of neutrons (Concept 4.2)
12. radioactive isotope- isotope in which the nucleus decays (breaks down) over time, giving off
radiation in the form of matter and energy (Concept 4.2)
13. ionic bond- chemical bond that occurs when an atom transfers an electron to another atom
(Concept 4.3)
14. ion- atom that has become electrically charged as a result of gaining or losing an electron
(Concept 4.3)
15. covalent bond- chemical bond that forms when two atoms share electrons (Concept 4.3)
16. molecule- two or more atoms held together by covalent bonds (Concept 4.3)
17. chemical reaction- breaking of old and formation of new chemical bonds that result in new
substances (Concept 4.3)
18. reactant- starting material for a chemical reaction (Concept 4.3)
19. product- material created as a result of a chemical reaction (Concept 4.3)
20. polar molecule- molecule in which opposite ends have opposite electric charges (Concept 4.4)
21. hydrogen bond- bond created by the weak attraction of a slightly positive hydrogen atom to a
slightly negative portion of another molecule (Concept 4.4)
22. cohesion- tendency of molecules of the same kind to stick to one another (Concept 4.4)
23. adhesion- attraction between unlike molecules (Concept 4.4)
24. thermal energy- total amount of energy associated with the random movement of atoms and
molecules in a sample of matter (Concepts 4.4, 7.2)
25. temperature- measure of the average energy of random motion of particles in a substance
(Concept 4.4)
26. solution- uniform mixture of two or more substances (Concept 4.4)
27. solvent- substance in a solution that dissolves the other substance and is present in the greater
amount (Concept 4.4)
28. solute- substance in a solution that is dissolved and is present in a lesser amount (Concept 4.4)
29. aqueous solution- solution in which water is the solvent (Concept 4.4)
30. acid- compound that donates H+ ions to an aqueous solution and measures less than 7 on the
pH scale (Concept 4.4)
31. base- compound that removes H+ ions from an aqueous solution and that measures more than 7
on the pH scale (Concept 4.4)
32. pH scale- a range of numbers used to describe how acidic or basic a solution is; ranges from 0
(most acidic) to 14 (most basic) (Concept 4.4)
33. buffer- substance that maintains a fairly constant pH in a solution by accepting H+ ions when
their levels rise and donating H+ ions when their levels fall (Concept 4.4)