Chapter 2 Biology 110
element
substances that can not be broken down into simpler substances by ordinary chemical means
Electrons
when atoms form bonds, they share or exchange
Single
which covalent bond involves only 2 electrons ( 1 pair)
Hydrogen- very electronegative
which of the following elements is mismatched with its properties or function.
1000; acidic
A pH of 4 is ___ times more ___ than a pH of 7
slightly acidic
A solution having a pH of 6 would be
Adhesion and cohesion
A stalk of celery is placed in a solution of blue colored dye. After on hour, the leaves have blue fluid in their veins. which property of water is being demonstrated?
Acidic
A substance containing more H+ and less OH- would be
Cannot be broken into simpler substances by chemical reactions
An element is defined as a substance that
Involves only valence electrons
Any chemical interaction between atoms:
one
Chlorine has seven electrons in its valence shell. The number of electrons it must gain to complete its valence shell is:
non polar
Covalently bonded atoms that share electrons equally are.
A single covalent bond
H-H
Oxygen, Hydrogen
In a water molecule, because oxygen is more electronegative than hydrogen, the shared electrons are more commonly found around the ____ nucleus than the _____ nucleus
They must have a partial negative charge
In living things, hydrogen bonds typically form between hydrogen and nitrogen or hydrogen and oxygen. What property must oxygen or nitrogen have for this bond to occur?
Sodium donates on electron to chlorine
In the formation of common table salt, sodium and chlorine interact because
Neutrons only
Isotopes differ from each other with respect to the number of:
Number of valence electrons
The chemical reactivity of an atom is determined most directly by the:
Hydrogen bonds
The cohesiveness between water molecules is due largely to:
Hydrogen and oxygen share an electron pair.
The covalent bond between a hydrogen atom and the oxygen atom in water is formed when;
An ion has an unequal number of protons and electrons, while an atom has an equal number
The difference between an electrically neutral atom and an ion is that:
Determines the chemical properties of the atom
The outer electron energy level of an atom
Protons
The particular type of element is determined by the number of
Non polar covalent bond and polar covalent bond
This bond is the result of two atoms sharing electrons in such a way that each atom has a full valence shell
acting as a buffer
When a small amount of hydrochloric acid is added to a solution of Na2HPO4, the pH of the solution does not change markedly. The pH also does not change drastically when a small amount of sodium hydroxide (NaOH) is added to this same solution. Based these observations, the compound Na2HPO4 is
C6H12O6 and 6 O2
Which of the following choices correctly identifies a reactant in the following chemical equation
S
Which of the following elements is NOT responsible for a significant portion of the mass of living organisms
They each have 6 protons
Which of the following facts allows you to determine that atom A and atom B are isotopes of the same element
Compared to other substances, little energy is required to raised or lower the temperature of water
Which of the following statements is not correct?
