Mastering Biology Assignment 1: Atoms and Chemistry of Life PDF

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Mastering Biology assignment for ABIO 121 that covers topics such as atoms, pH, and electromagnetism. ...

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Mastering Biology

7.

In salt, what is the nature of the bond between sodium and chlorine?

Assignment 1 1.

ANSWER: Ionic

What is the atomic number of an atom that has

Sodium and chlorine ions are attracted to

6 protons, 6 neutrons, and 6 electrons?

each other.

ANSWER : 6

8.

What is the result of the animated process?

This is an atom of carbon, an element with 6 protons. Atomic number is the number of protons in an atom. 2.

Which of these refers to atoms with the same 

atomic number but different atomic masses? ANSWER: These atoms are isotopes. Atoms with the same atomic number and different atomic masses are referred to as isotopes. 3.

Fluorine's atomic number is 9 and its atomic mass is 19. How many neutrons does fluorine have?

4.

ANSWER: 10

and a negatively charged chlorine ion

Atomic mass is equal to the number of

Sodium loses an electron and thus becomes

protons plus the number of neutrons (19-9

positively charged; chlorine gains an

= 10).

electron and thus becomes negatively

An uncharged atom of boron has an atomic

charged. There is no overall gain of

number of 5 and an atomic mass of 11. How

electrons from the system illustrated here.

many protons does boron have?

5.

9.

An ionic bond involves _____.

ANSWER: 5

ANSWER: an attraction between ions of

The atomic number is equal to the number

opposite charge

of protons.

This is the definition of an ionic bond.

How can you determine the approximate mass of an atom, in atomic mass units?

6.

ANSWER: a positively charged sodium ion

10. The innermost electron shell of an atom can hold up to _____ electrons.

ANSWER: Add up the number of protons

ANSWER: 2

and neutrons

This is the maximum number of electrons

Atoms with the same number of protons but

that can occupy the innermost electron

with different electrical charges _____.

shell.

ANSWER: are different ions Ions are charged atoms.

11. Which of these relationships is true of an uncharged atom?

ANSWER: The number of protons is equal

14.

to the number of electrons In this situation the number of positive charges is equal to the number of negative charges. 12. What determines the types of chemical reactions that an atom participates in? ANSWER: the number of electrons in the outermost electron shell An atom is least likely to participate in a reaction when its outermost shell is stable.

The proton and neutron both have masses of about 1 amu, whereas the electron mass

13. The proton, neutron, and electron are the three main subatomic particles that make

is only about 5.5×10−4amu. Featured Image and Info.

up all the elements. All matter is made up of atoms. An atom has a nucleus consisting of positively charged protons and uncharged neutrons. Negatively charged electrons are found outside of the nucleus of the atom

15. An atom has six electrons in its valence shell.

An oxygen atom needs two additional

How many single covalent bonds would you

electrons to fill its outer shell. Thus, it can

expect it to form in most circumstances?

form two single covalent bonds.

ANSWER: Two Featured Information

16.

A covalent bond is the sharing of a pair of outer-shell electrons by two atoms. For example, each of these hydrogen atoms has one electron in its outer shell, but needs two electrons to complete its outer shell. If the two hydrogen atoms share electrons, they can both complete their outer shells. The shared pair of electrons constitutes a covalent bond-- shown in shorthand as a line. The covalently-bonded hydrogen atoms form a molecule of hydrogen gas. A molecule is defined as two or more atoms held together by covalent bonds.

An oxygen atom needs two electrons to complete its outer shell. Two oxygen atoms can share two pairs of electrons. A

17. A(n) _____ refers to two or more atoms held together by covalent bonds.

molecule of oxygen gas is held together by

ANSWER: molecule

a double covalent bond-- two shared pairs

A molecule is defined as two or more atoms

of electrons.

held together by covalent bonds.

A carbon atom needs four electrons to complete its outer shell. It can share electrons with four hydrogen atoms, forming a methane molecule containing four single covalent bonds. Methane is a compound, a substance formed by the combination of two or more elements. We call methane natural gas; it is the fuel burned in gas stoves and furnaces.

ANSWER: The oxygen atom in a water molecule has a partial negative charge. The oxygen atom attracts electrons more strongly than the hydrogen atoms, so the oxygen atom has a partial negative charge. 23. Why does water require so much energy to change its phase? ANSWER: Water has a large number of hydrogen bonds. A large amount of energy is required to 18.

break the hydrogen bonds between water molecules and allow heat to be transferred. 24. If an atom has a charge of -2, which of the following must be true? ANSWER: It has two more electrons than protons. Featured Images and Info

19.

20. Which term describes the degree to which an element attracts electrons? ANSWER: Electronegativity Electronegativity is the tendency of an atom to attract electrons toward itself. 21. Which terms describe two atoms when they form a bond in which electrons are completely transferred from one atom to the other? ANSWER: Anion and cation Each atom will carry a charge from the transfer of electrons. 22. Which of the following statements about the atoms in a water molecule is true?

An acid is any substance that increases the H+ concentration of a solution. A base is any substance that reduces the H+ concentration of a solution. 25. In a neutral solution the concentration of _____. ANSWER: hydrogen ions is equal to the concentration of hydroxide ions This is the definition of a neutral solution. 26. When one of the atoms involved in a covalent bond has a much higher electronegativity than the other atom, what type of bond results? ANSWER: a polar covalent bond 27. What holds electrons in a covalent bond? ANSWER: The negative charges on the electrons are attracted by the positive charges on both nuclei....