Basic Chemistry

14. True or False? Protons have a positive charge. a. True.

That statement is true. Electrons are negatively charged and neutrons are neutral.

15. The first three rings of an atom should hold how many electrons each? 2, 2, 2 2, 2, 8 2, 4, 8 2, 8, 8 d.

Remember the rule of eights Remember the rule of eights. Except for the first shell, eight is the preferred number.

16. The symbol for potassium is K Pm c.

K is the symbol for potassium; P is phosphorus K is the symbol for potassium; P is phosphorus. The symbols for some elements come from their Latin names.

16. How many protons and electrons does hydrogen have? 1,1 1,2 1,3 4,4 a.

Hydrogen, the simplest atom, has one proton and one electron. The number of protons should equal the number of electrons in an atom. Answers b and c represent isotopes of H.

17. If an element had 6 protons, 10 neutrons, and 6 electrons, what would its atomic mass be? 12 16 d.

An element with 6 protons, 10 neutrons and 6 electrons has an atomic mass of 16. The atomic mass of an element is the sum of its protons and neutrons. The atomic number is the number of protons, which equals the number of electrons.

18. What is the valence shell? The first shell of electrons An incomplete shell of electrons The last shell of electrons The sum of all the electrons c.

The valence shell is the number of electrons in the last shell The valence shell is the number of electrons in the last shell. This determines the reactivity of the atom. All atoms that need 1 to complete their valence shell are found in the first column of the periodic chart.

19. A bond that involves the transfer of electrons is called a(n) covalent bond. hydrogen bond. ionic bond. electronic bond. c.

Ionic bonds involve the transfer of electrons Ionic bonds involve the transfer of electrons. When atoms gain or lose electrons, they become charged and are attracted to atoms of the opposite charge. Covalent bonds involve the sharing of electrons. Note the prefix co- as in cooperate and cohabitate.

20. Which pH is most acidic? 2 5 7 9 11

2 is most acidic. 7 is neutral. 11 is most basic.

21. How many more time acidic is a pH of 2 than a pH of 5? 3 10 100 1000 1,000,000

1000 times. Each number represents a 10x increase in acid or basic properties

22. Where is the chemical energy in a molecule? Chemical bonds Protons Neutrons Electrons

Chemical energy is in the chemical bonds.

23. Which of the following is an INORGANIC molecule? Water Carbohydrates Lipids Proteins Nucleic acids

Water is the only inorganic molecule Water is the only inorganic molecule. The others are the main groups of organic molecules.