Biology chapter 2

acid- netrual- base-

0 -6.99 7 7.01-14

An atom of carbon has 6 protons, 6 neutrons, and 6 electrons. Its mass number is ______.

12

An element with 6 protons and 7 neutrons would have a mass number of

13

An atom with 4 electron shells and 5 electrons in the outer shell would be where on the periodic table?

4th period, 5th group

create a balanced equation for the process of photosynthesis: 6 CO2 + _____ H2O --> C6H12O6 + ____ O2

6 / 6

On the periodic table, what are the letter designations, such as Fe and H, called?

Atomic symbols

How is an elements atomic mass determined?

Averaging the mass numbers for all atoms of an element.

Which one of these is a chemical or combination of chemicals that prevent changes in pH?

Buffer

_______ bonds involve sharing of electrons between atoms, while ________ bonds involve the movement of electrons from one atom to the other.

Covalent, Ionic

The atomic symbol for the element Hydrogen is

H

When dissociated into water, what type of particles do acids release?

Hydrogen ions

Which characteristic applies to a substance that is a base?

It has a low hydrogen ion concentration.

What do the number of electrons in an atoms valence shell determine?

Its chemical reactivity.

Anything that has mass and takes up space is, by definition,

Matter

Which subatomic particle will have a positive electrical charge?

Proton

Which statement describes an acidic solution on the pH scale?

The hydrogen ion concentration is greater than the hydroxide concentration.

Which feature of water molecules causes them to be attracted to each other?

Their polarity.

What is the goal for elements that form an ionic bond?

To have a complete valence shell.

Which description characterizes an ionic bond?

Two atoms are bonded due to an attraction between opposite charges.

Which statement best describes a covalent bond?

Two atoms share electrons so they can have a complete valence shell.

The outermost electron shell of an atom is called its _______ shell.

Valence

What are the properties of water?

Water is cohesive and adhesive. Water has a varying density. Water has a high heat capacity. Water has a high surface tension. Water dissolves many different substances. water is a good solvent

Which of the following is NOT one of the properties of water?

Water is nonpolar.

Which bond forms between adjacent molecules of water?

a hydrogen bond

A solution with a higher concentration of hydrogen (H+) ions than hydroxide (OH-) ions is an example of a(n) _____.

acid

Any solution with a pH less than 7 is

acid

Substances that dissociate in water and release hydrogen ions are called

acids

The periodic table provides which of the following information regarding an element?

atomic mass atomic number atomic symbol

Elements are composed of smaller particles called

atoms

A ______ solution will have a pH value between 7.01 and 14.

base or basic

Which of the following are ingredients for the process of photosynthesis?

carbon dioxide, water

What are the four elements that make up 96% of the body weight of most organisms and are essential to all life.

carbon, hydrogen, nitrogen and oxygen

An atom's electronegativity will influence the atoms affinity for electrons when it is forming a ______ bond.

covalent

An atom's electronegativity will influence the atoms affinity for electrons when it is forming a _______ bond.

covalent

When two hydrogen atoms share an electron with each other, they will form a(n) _______ bond.

covalent

The carbon and hydrogen atoms in methane (CH4) are held together by _____ bonds. The sodium and chlorine atoms in sodium chloride (NaCl) are held together by _____ bonds.

covalent; ionic

In an atom, which of these represents the energy of electrons, but not necessarily their physical location?

electron shell

The period number tells how many ______ an atom has, while the group number denotes how many ______.

electron shells, electrons it has on the outer shell

Which of these terms identifies the affinity, or attraction, that an atom has for electrons?

electronegativity

A subatomic particle with a negative charge is called a(n)

electrons

The ______ are found outside of the nucleus of an atom

electrons

Which subatomic particle orbits outside the atomic nucleus and carries a negative electrical charge?`

electrons

A substance that cannot be broken down into simpler substances by ordinary chemical means is called a(n) _____.

element

Which of the following are end products of photosynthesis?

glucose and oxygen

Potassium (K), Sodium (Na), and Hydrogen (H) are located in the same _______ of the periodic table.

group

Buffers keep the pH in the human body within a narrow range so it can help maintain

homeostasis

A basic solution will take up ______ions while it releases hydroxide ions.

hydrogen

A(n) ______ bond results from the attraction between a slightly positive hydrogen atom in one water molecule and a slightly negative oxygen atom in another water molecule.

hydrogen

A basic solution will take up ______ ions while it releases hydroxide ions.

hydrogen or H

Water disassociates to produce a(n) ______ ion with a positive charge and a hydroxide ion with a negative charge.

hydrogen or H+

A buffer will resist changes in pH because they take up excess ______ and ______ ions.

hydrogen, hydroxide

When water dissociates, it releases an equal number of hydrogen ions (H+) and

hydroxide ions (OH-).

When a water molecule dissociates, the _______ion, which bears a negative charge, is produced.

hydroxide or OH-

A hydrogen atom that has lost its electron, and therefore bears a positive charge, is called a hydrogen

ion or cation

Atoms of the same element that differ in the number of neutrons they contain are known as

isotopes

During an ionic bond between sodium and chloride, the sodium will _________ its electron.

lose or donate

The ______ number of an atom is determined by adding together the number of protons and neutrons.

mass

Since the number of neutrons may differ between atoms of an element, the atomic ______represents the average of the mass numbers.

mass or weight

A group of atoms of one or more element bonded together is called a

molecule

When two hydrogen atoms bond together they are forming a(n) ______.

molecule

A neutron has a _____ electrical charge.

neutral

Protons and _____ are found in an atom's nucleus.

neutrons

The mass number of an atom is calculated by adding the number of protons to the number of _____.

neutrons

In what way do isotopes differ from each other?

number of neutrons

Electron shells with eight electrons in them are the most stable, according to the ____ rule.

octet

If an atom has two or more shells, the outer shell is most stable when it has eight electrons, according to the

octet rule.

In a polar covalent bond, atoms on both sides of the bond are ______ charged.

partially

In the periodic table, horizontal rows are called ____ , while vertical columns are called ____.

period, group

Since oxygen nuclei have a greater affinity for electrons than do hydrogen nuclei, what type of bond is typical of water molecules, H2O?

polar covalent bond

Neutrons and _____ exist in the center of an atom, while electrons are around the outside.

protons

The subatomic particles located in the nucleus that have a positive charge are called

protons

To determine the atomic number of an atom you will need to know how manym______ are in its' nucleus.

protons

Which subatomic particle is used to determine an atoms atomic number?

protons

Electrons are located in energy levels called electron _______ that will surround the atom's nucleus.

shells

Identify the states of matter.

soild, liquid, gas and plasma