Bio I - 2 Flashcards
What are organisms composed of?
Matter
What is matter?
Anything that has mass and takes up space
What is an element?
An element is a substance that cannot be broken down to other substances by chemical reactions
What is a compound?
A compound is a substance consisting of two or more elements in a fixed ratio
How many elements were in the original periodic table and who invented it and when?
Dimitri Mendeleev in 1869 developed the periodic table with 56 elements
On the periodic table, what are the elements arranged by?
Structure
metallic classification
electronegativity
How many columns/groups are there in the periodic table?
18
 but we number eight of them as a groups
What are the rows called and how many are there?
Periods
7
What are group 1A?
Alkali metal
What is group 2A?
Alkaline earth metals
What is group 6A?
Chalcogens (ore formers)
What is group 7a?
Halogens (salt formers)
What is Group 8a?
Noble gasses (they have eight electrons in their outer most shell)
Are group 1A and 2A metal?
Yes
Are groups 4a 5a and 6A metals?
Partially metal and non-metal
What are the B groups?
The b groups are transition medals which means they can exist in multiple charges
What are metalloids?
They are the elements that fall in the border between metal and nonmetals in groups 3a to 6a and they have properties of both metals and nonmetals
What percentage of the 92 elements are essential to life?
20-25%
Which elements make up 96% of living matter?
Carbon, hydrogen, oxygen, and nitrogen
What does the remaining 4% of what is essential to life made up of? (7)
Calcium, phosphorus, potassium, sulfur, sodium, chlorine, and magnesium 
What are trace elements?
Trace elements are those required by an organism and only minute quantities
Examples include - Boron, chromium, cobalt, copper, fluorine, iodine, iron, manganese…
What is an atom?
An atom is the smallest unit of matter that still retains the properties of an element
What are the subatomic particles that atoms are composed of?
Protons
Electrons
Neutrons
What is the atomic nucleus made of?
Protons and neutrons
Where are the electrons positioned?
They form a cloud around the nucleus
What are Daltons?
Neutron mass and proton mass are almost identical and they are measured in Dalton’s
What are valence electrons?
They are electrons in the outermost level (or valence level)
The valence electrons determine the chemical behavior of an atom
What causes a chemical bond?
When atoms with incomplete valence levels share or transfer valence electrons with other atoms this usually results in atoms staying close together held by attractions called chemical bonds
What is a covalent bond?
It is the sharing of a pair of valence electrons by two atoms
What is a molecule?
A molecule consist of two or more atoms held together
What is a single bond?
A single covalent bond or single bond is the sharing of one pair of valence electrons
What is a double bond?
A double covalent bond or double bond is a sharing of two pairs of valence electrons
What is the structural formula?
The notation used to represent Atoms and bonding
What is a molecular formula?
When a structural formula is abbreviated further
For example -
Structural formula H—H
Molecular formula H2
What is the atoms valence?
The atoms bonding capacity
What is electronegativity?
An atoms attraction for the electrons in a covalent bond
The More electronegative an atom the more strongly it pulls shared electrons toward itself
What is a nonpolar covalent bond?
When the atom share the electron equally
What is a polar covalent bond?
When one atom is more electronegative and the atoms do not share the electron equally
What causes a partial positive or negative charge for each atom or molecule?
Unequal sharing of electrons
What happens after the transfer of an electron?
Both atoms have charges
What is an ion?
A charged atom or molecule
What is an ionic bond?
A bond between atoms where electrons are transferred from one to another
What is a cation?
Cation is a positively charged ion
What is an anion?
An anion is a negatively charged ion
What is an ionic bond in regards to cations and anions?
It is an attraction between an anion and a cation
What are compounds called that are formed by ionic bonds?
Ionic compounds or salts
What is a hydrogen bond?
Hydrogen bond forms when a hydrogen atom covalently bonded to one electronegative atom is also attracted to another Electronegative atom 
What is a simpler way to describe a hydrogen bond?
The hydrogen bond is an attraction between two atoms that already participate in other chemical bonds. One of the atoms is hydrogen while the other may be any electronegative atom such as oxygen chlorine or fluorine 
What is Vanderwall’s interactions?
If electrons are distributed asymmetrically in molecules or atoms they may accumulate by chance in one part of a molecule. Vanderwall‘s interactions are attractions between molecules that are close together as a result of these charges. 
What is a chemical reaction?
Chemical reactions are the making and breaking of chemical bonds
What are the starting molecules of a chemical reaction called?
Reactants
What are the final molecules of a chemical reaction called?
Products
What is the chemical equilibrium?
Chemical equilibrium is a condition in the course of the reversible chemical reaction in which no net change in the amounts of reactants and products occurs
What are isotopes?
They are atoms with the same amount of protons but different amount of neutrons. They are different forms of a single element. For example carbon 12 and carbon 14 are both isotopes of carbon one with 6 neutrons and one with 8 neutrons
