Chapter 2 Flashcards
Study Guide
Describe the basic structure of an atom (including nucleus and shells)
The nucleus is in the middle of an atom and contains protons and neutrons. The electrons are located on shells surrounding the nucleus. The first shell holds 2 electrons and the others hold 8.
What is the significance of an octet?
An atom is most stable with 8 electrons in its outer (valence shell). Atoms can share, give up, or steal electrons to get to 8.
Define Ionic Bond. How does it relate to the octet rule
An ionic bond is formed due to opposite attraction. This bond can be formed over an atom having 7 electrons in its outer shell and another having 1. The atom with 1 wants to get rid of 1 and the atom with 7 wants to gain 1. The two atoms come together for a short period of time. The atom with 1 electron gives it up to the atom with 7 and the bond breaks apart.
Define Covalent Bond. How does it relate to the octet rule?
A covalent bond is formed due to the sharing of electrons. This can satisfy the octet rule because atoms can share 1 or multiple electrons to get to 8 in their valence shell.
What is a hydrogen bond?
A hydrogen bond is a weak bond between a hydrogen molecule and another molecule due to a high affinity for electrons.
What are the properties of water?
Will have to relate them to hydrogen bonding
Solvent High surface tension High heat of vaporization Varying density Cohesion and Adhesion
How does water being a solvent relate to hydrogen bonding
Due to polarity and H-bonding water dissolves many substances.
Hydrophobic
Water hating
Doesn’t dissolve in water
Hydrophililc
Water loving
Dissolves in water
How does a High surface tension relate to hydrogen bonding?
The hydrogen atoms in water cling more tightly to each other than they do to the air above
How does a high heat of vaporization relate to hydrogen bonding
It take a lot of energy to break hydrogen bonds for evaporation. This is why the temperature of water rises and falls so quickly
How does varying density relate to hydrogen bonding
Ice is less dense than water, the H2O molelcules spread apart when frozen, which makes ice float, and life on earth possible.
How does Cohesion and Adhesion relate to hydrogen bonding?
Cohesion holds hydrogen molecules together, whereas adhesion forces pull the water molecules towards other molecules. This is what make is possible for plants and trees to take up water.
What is an Acid
Anything that is lower than 7 on the pH scale
More H+ than OH-
What is a Base
Anything that is higher than 7 on the pH scale
More OH- than H+
