BIO 1107 CHPT 2

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

10

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

2

This atom can form up to _____ single covalent bond(s). The figure shows an atom with two electron shells. There is one electron pair in the inner electron shell and four unpaired electrons in the outer electron shell.

4 ELECTRONS ARE IN THE OUTERMOST SHELL

An uncharged atom of boron has an atomic number of 5 and an atomic mass of 11. How many protons does boron have?

5

What is the atomic number of an atom that has 6 protons, 6 neutrons, and 6 electrons?

6

The mass number of an atom is 15, and its atomic number is 7. The atom probably has...

8 NEUTRONS IN THE NUCLEUS

An atom has 8 protons, 8 neutrons, and 8 electrons. Another isotope of the same element might have ...

8 PROTONS OR 10 NEUTRONS

We can represent atoms by listing the number of protons, neutrons, and electrons-for example, 2p +, 2n 0, 2e - for helium. Which of the following represents the 18O isotope of oxygen?

8p+, 10n^0, 8e-

What happens when two atoms form a chemical bond?

A CHEMICAL BOND FORMS WHEN TWO ATOMS TRANSFER OR SHARE OUTER ELECTRONS TO COMPLETE THEIR OUTER SHELLS

Which of the following statements is NOT TRUE?

A PATIENT SUFFERING FROM A GOITER SHOULD NOT CONSUME SEAFOOD ALL LIFE REQUIRES THE SAME ESSENTIAL ELEMENTS CARBON, HYDROGEN, OXYGEN, AND CALCIUM ARE THE MOST ABUNDANT ELEMENTS OF LIVING MATTER

Radioactive decay is likely to occur when ..

AN ATOM HAS TOO MANY NEUTRONS The atomic nucleus becomes unstable if the ratio of protons to neutrons is too far from unity

An ionic bond involves _____.

AN ATTRACTION BETWEEN IONS OF THE OPPOSITE CHARGE.

Atoms with the same number of protons but with different electrical charges _____.

ARE DIFFERENT IONS. Ions are charged atoms.

Which of the following lists some of the levels of biological organization from less complex to more complex?

ATOMS MOLECULES CELLS ORGANS

Electrons are held in an atom by attraction to what particle or location?

ATTRACTION TO THE POSITIVELY CHARGE PROTONS IN THE NUCLEUS

About 25 of the 92 natural elements are known to be essential to life. Which 4 of these 25 elements make up approximately 96% of living matter?

CARBON HYDROGEN NITROGEN OXYGEN

An atom has 6 electrons, 6 protons, and 6 neutrons. You can tell that this atom belongs to the element _____ because _____________________.

CARBON (C); IT HAS 6 PROTONS

What type of bond is joining the two hydrogen atoms? The figure shows two hydrogen atoms, which share two electrons.

COVALENT BOND

A(n) _____ bond joins these two oxygen atoms. The figure shows two oxygen atoms with two electron shells, which share four electrons located in their outer electron shells. Each atom also has one electron pair in the inner electron shell and two electron pairs in the outer electron shell.

DOUBLE COVALENT BOND

Compare the three atom diagrams. Which one shows the electron with the highest potential energy?

Diagram of an atomic nucleus with three electron shells. The first shell is closest to the nucleus. The second shell is farther away from the nucleus than the first shell. The third shell is farthest away from the nucleus. An electron is shown in the third shell. THE ELECTIONS FURTHEST AWAY FROM THE NUCLEUS IS THE ONE WITH THE MOST POTENTIAL ENERGY

Which statement is true of atoms?

ELECTRONS DETERMINE THE ATOM'S SIZE

A substance that cannot be broken down into other substances by ordinary chemical procedures is a(n) _____.

ELEMENT

Which statement is most useful in explaining why chemists assign atoms to chemical elements by counting protons?

ELEMENTS ARE DEFINED BY THE NUMER OF PROTONS

Which of the following are compounds?

H2O AND CH4 , BUT NOT O2 (same element)

The atomic number of sulfur is 16. Sulfur combines with hydrogen by covalent bonding to form a compound, hydrogen sulfide. Based on the number of valence electrons in a sulfur atom, predict the molecular formula of the compound.

H2S

The atoms of different phosphorus isotopes _____.

HAVE DIFFERENT NUMBER OF NEUTRONS BUT SAME NUMBER OF PROTONS

When an electron loses a discrete amount of energy, it moves from a .....electron shell to a....electron shell, which is... the nucleus.

HIGHER LOWER CLOSER TO

The brackets are indicating a(n) _____ bond. The figure shows a bond between two molecules. Each molecule consists of two small atoms, which connect to the bigger one. This bond is formed between one of the small atoms from one molecule and the big atom from the other molecule. This small atom has a delta plus charge, and the big atom has a delta minus charge. This bond is marked by three points.

HYDROGEN BOND

What name is given to the bond between water molecules?

HYDROGEN BOND A hydrogen atom with a net positive charge is attracted to an oxygen atom with a net negative charge.

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

IONIC Sodium and Chlorine ions are attracted to each other.

What can happen to an electron when sunlight hits it?

IT CAN STAY IN ITS ORIGINAL SHELL IT CAN MOVE OUT TO A HIGHER ELECTRON SHELL IF ENOUGH SUNLIGHT ENERGY IS GIVEN

When an electron absorbs the required amount of light energy, it moves from a.....electron shell to a.... electron shell, which is... the nucleus.

LOWER HIGHER FARTHER FROM

Which of the following is a trace element required by most living organisms?

MANGANESE/MAGNESIUM

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

MOLECULE

A carbon atom and a hydrogen atom form what type of bond in a molecule?

NONPOLAR COVALENT BOND

An ionic bond is formed when _____.

ONE ATOM TRANSFERS AN ELECTRON TO ANOTHER ATOM

VALENCE SHELL

OUTERMOST ELECTRON SHELL

Which model most accurately represents the current view of the structure of the atom?

PROBABILITY MODEL

Which of the following subatomic particles always has a positive charge?

PROTONS

Changing the number of _____ would change an atom into an atom of a different element

PROTONS IN AN ATOM

What type of bond joins the carbon atom to each of the hydrogen atoms? The figure illustrates a molecule, which consists of four hydrogen atoms and one carbon atom. Hydrogen atoms are connected to the carbon atom by an electron pair each. These electron pairs are located at the intersection of the electron shell of hydrogens and the outer electron shell of the carbon atom. Moreover, the carbon atom has its own electron pair in the inner electron shell.

SINGLE (NONPOLAR) COVALENT BOND

Which of the following statements is TRUE?

SOME NATURALLY OCCURRING ELEMENTS ARE TOXIC TO ORGANISMS

ELECTRON

SYMBOL e -1 CHARGE MASS OF ~1/2000 AMU ( 5.5×10−4amU)

NEUTRON

SYMBOL n 0 CHARGE MASS OF ~1 AMU

PROTON

SYMBOL p +1 CHARGE MASS OF ~1 AMU

Which statement is true of all atoms that are anions?

THE ATOM HAS MORE ELECTRONS THAN PROTONS. (ANION = NEGATIVE)

Which statement is true of the atom shown in the diagram? There is an atomic structure: six negatively charged particles are around the nucleus. One negatively charged particle is in the inner shell, and another five are in the outer shell.

THE ATOMS IS IN THE EXCITED STATE A ELECTRON WILL MOVE FROM THE OUTER TO THE INNER SHELL THE ATOM HAS MORE THAN ONE VALENCE ELECTRON

The reactivity of an atom arises from

THE EXISTENCE OF UNPAIRED ELECTRONS IN THE VALENCE SHELL

Dr. Jones says an atom has 3 electrons in the first shell and four electrons in the second shell. Someone should tell Dr. Jones that ...

THE FIRST SHELL SHOULDN'T HAVE 3 ELECTRONS BECAUSE THE FIRST SHELL CAN ONLY HOLD 0,1,OR 2 ELECTRONS.

Chemical equilibrium is reached when _____.

THE FORWARD AND REVERSE REACTIONS OCCUR AT THE SAME RATE SO THAT THE CONCENTRATIONS OF REACTANTS AND PRODUCTS REMAIN THE SAME

Given what you know about the human body, what do you think accounts for the high percentage of oxygen (65.0%)?

THE HUMAN BODY IS MADE UP MAINLY OF WATER, AND THERE IS ONE OXYGEN ATOM IN EVERY WATER MOLECULE

Which of these relationships is true of an uncharged atom?

THE NUMBER OF PROTONS IS EQUAL TO THE NUMBER OF ELECTRONS

What determines the types of chemical reactions that an atom participates in?

THE NUMBER OF THE ELECTRONS IN THE OUTERMOST ELECTRON SHELL

The type of bonding and the numbers of covalent bonds an atom can form with other atoms is determined by _____.

THE NUMBER OF THE UNPAIRED ELECTRONS IN THE VALENCE SHELL

Which of the following statements correctly describes any chemical reaction that has reached equilibrium?

THE RATES OF THE FORWARD AND REVERSE REACTIONS ARE EQUAL

Two atoms always represent the same element if they have ...

THE SAME NUMBER OF PROTONS

Which statement is true of the energy levels of electrons in shells?

THE VALENCE SHELL HAS HIGHER ENERGY THAN OTHER OCCUPIED SHELLS

Which of these refers to atoms with the same atomic number but different atomic masses?

THESE ATOMS ARE ISOTOPES

Which of these figures correctly illustrates the nature of the bonding of H2O?

The figure illustrates the possible nature of the bonding of a molecule of water. Hydrogen atoms are connected to the oxygen atom by an electron pair each. Moreover, oxygen atom has its own three electron pairs. One of these pairs is located in the inner electron shell. Two other pairs are located in the outer electron shell. The oxygen atom has a negative charge. Two hydrogen atoms have positive charges.

Which statement about weak bonds is correct?

WEAK BONDS ARE TRANSIENT AND EASILY REVERSIBLE

Hydrogen bonding is most often seen _____.

WHEN HYDROGEN IS COVALENTLY BONDED TO AN ELECTRONEGATIVE ATOM Highly electronegative atoms attract shared electrons more strongly than hydrogen does, resulting in a slight positive charge on the hydrogen atom. The slightly positive hydrogen atom is then attracted to another electronegative atom, forming a hydrogen bond.

ELECTRONEGATIVITY

a measure of the tendency of an atom to attract a bonding pair of electrons.