Chapter 2: The Chemical Basis of Life I - Atoms, Molecules and Water

Fill-in-the-blank practice flashcards covering subatomic particles, electron configuration, atomic mass and number, chemical bonding, water interactions, pH, and buffers based on Chapter 2 study solutions.

A substance composed of only one type of atom is called an __________..

element

Protons are subatomic particles located in the __________ and carry a positive charge.

nucleus

Neutrons are subatomic particles located in the nucleus that carry a __________ charge.

neutral (no charge)

Electrons carry a negative charge and are located in __________ surrounding the nucleus.

orbitals (or electron shells)

The maximum number of electrons that can occupy the first electron shell is __________..

$$2$$

The second electron shell contains one s orbital and three p orbitals, holding a maximum of __________ electrons.

$$8$$

The s and p orbitals of the third electron shell can hold up to __________ electrons.

$$8$$

Electrons that participate in chemical bonding are located in the outer shell and are called __________ electrons.

valence

An atom of Carbon ($C$) has a total of $6$ electrons, with $2$ in the first shell and __________ in the second shell.

$$4$$

An atom of Aluminum ($Al$) has a total of $13$ electrons and contains __________ valence electrons.

$$3$$

The __________ number gives the number of protons in an atom.

atomic

Atomic mass is determined by calculating the total mass of the protons and __________ in an atom.

neutrons

Helium ($He$) has an atomic number of $2$ and an atomic mass of __________..

$$4.003$$

Nitrogen ($N$) has an atomic number of $7$ and an atomic mass of __________..

$$14.067$$

Sulfur ($S$) has an atomic number of $16$ and an atomic mass of __________..

$$32.066$$

Atoms of the same element that have the same number of protons but a different number of neutrons are called __________..

isotopes

The atomic mass of an element is not a whole number because it represents the __________ mass of its different isotopes.

average

A single molecule of glucose ($C_6H_{12}O_6$) contains $6$ carbon atoms, $6$ oxygen atoms, and __________ hydrogen atoms.

$$12$$

A __________ is defined as a molecule composed of more than one element.

compound

While $H_2O$ is a compound, __________ is not a compound because it contains only one element type.

$$O_2$$

The molecular mass of ammonia ($NH_3$) is equal to __________..

$$17$$

The molecular mass of carbon dioxide ($CO_2$) is equal to __________..

$$44$$

An atom that has gained electrons acquires a negative charge and becomes a negatively charged __________..

ion

An atom that has lost electrons acquires a charge and becomes a __________ charged ion.

positively

In the chemical interaction diagram labelled C, the attractive force shown between a partially positive hydrogen atom and a partially negative atom is a __________ bond.

hydrogen

Bonding electrons shared equally between two atoms with no charges on the atoms form a __________ covalent bond.

non-polar

Temporary attractive forces between neutral atoms due to temporary uneven distribution of electrons are known as __________ forces.

Van der Waals

The complete transfer of one or more valence electrons resulting in full charges on ions forms an __________ bond.

ionic

Bonding electrons shared unequally between two atoms resulting in partial charges form a __________ covalent bond.

polar

Molecules that are 'water-loving' and dissolve well in water are termed __________..

hydrophilic

Hydrophobic molecules do not dissolve well in water because they possess predominantly __________ covalent bonds.

non-polar

Molecules containing both hydrophobic regions and hydrophilic regions are called __________ molecules.

amphipathic

When placed in water, amphipathic molecules form bilayers or __________ to sequester hydrophobic groups away from water.

micelles

pH is defined as a measure of __________ ion concentration.

hydrogen ($H^+$)

An acid increases hydrogen ion concentration and produces a solution with a pH __________ than 7.

less

A base decreases hydrogen ion concentration and produces a solution with a pH __________ than 7.

greater

The primary function of a buffer is to maintain a constant __________ in a solution.

pH

The carbonic acid/bicarbonate buffer system helps maintain a constant human blood pH of __________..

$$7.4$$