Practice Test Question
What constitutes an anion?
When the atom has more electrons than protons
Define an element. (Example?)
Substance that cannot be broken down to other substances by chemical reactions (Carbon, Nitrogen, Oxygen)
smallest unit of matter that still retains the properties of an element
an atom
Example of a chemical reaction?
2 H2 + O2 = 2 H2O
What are the three types of bonds we focused on in class?
Covalent, Ionic, and Hydrogen
When does a weak chemical bond such as a hydrogen bond form?
When a hydrogen atom that is covalently bonded to an electronegative atom like oxygen or nitrogen is attracted to another electronegative atom
Define a compound. (Example?)
a substance consisting of two or more elements in a fixed ratio. (Salt; NaCl, Water; H2O)
What are the three subatomic particles and their charges?
Proton (+), Electron (-), Neutron (=)
Define a chemical reaction.
How are ionic bonds different from covalent bonds?
Ionic bonds strip/steal electrons from their bonding partner while covalent bonds share their electrons.
In ionic interactions, the transfer of valence electrons results in what?
Completed valence shell for each ion.
What are trace elements? (Example?)
required elements but only in minute quantities. (Iron, Boron, Copper)
How would you find the number of neutrons in an element?
mass number - atomic number
The _____ are starting materials and the ______ are the resulting materials. (Fill in the blank)
Reactants, Products
What makes water (H2O) a polar covalent bond?
Because oxygen is more electronegative then hydrogen, the electrons are not shared equally
What does the reactivity of an atom arise from?
The existence of unpaired electrons in the valence shell.
What are the essential elements organisms need to live a healthy life and reproduce?
Oxygen, Carbon, Hydrogen, Nitrogen
What do electron shells tell you about potential energy?
more shells = more potential energy
(what else can cause more potential energy?)
The point at which the reactions offset one another exactly is called...
chemical equalibrium.
In living cells what two atoms are typically hydrogen bonding partners?
How do radioactive isotopes help scientists date fossils?
Radioactive dating allows scientists to determine an absolute age of fossils by determining how much of certain radioactive substances has decayed and how long it would have taken for that amount of decay to occur.
How does table salt have emergent properties?
A compound (salt) has characteristics different from those of its elements.
If two or more elements are in the same row what do they have in common?
The same number of orbitals/electron shells
(If two or more elements are in the same column what do they have in common?)
If the concentration of reactants is increased, what would you suspect would happen to the rate of reaction?
The reaction would increase, and become more frequent.
Why is molecular shape crucial?
It determines how biological molecules recognize and respond to one another. Biological molecules often bind temporarily to each other if their shapes are complementary.