Ch. 1 - 4 Review Flashcards
(94 cards)
List some of the characteristics that define “life”
- Common set of chemical components: carbohydrates, fats, nucleic acids, amino acids
- Cells enclosed by plasma membranes
- Convert molecules in environment to new molecules
- Extract energy from environment and use it to do biological work
- Contain genetic information with universal code to specify proteins
Identify general differences/similarities between prokaryotes and eukaryotes
Prokaryotes are unicellular organisms with a cellular membrane but no nucleus. Eukaryotes are made up of cells that have a cellular membrane, nucleus and organelles
What does it mean to have “differentiated” cells?
Cells that carry out specific functions
What is the definition of matter? An element? A compound?
Matter is anything that has mass and occupies space; element is the purest form of a substance; compound is a combination of elements in a fixed ratio
What are the 3 major atomic particles we discussed in class and what charges are associated w/ each?
Protons (positive), neutrons (neutral) and electrons (negative)
Where, within an atom, are the protons and neutrons located? Where are the electrons?
Protons and neutrons are located in the nucleus; electrons are located in orbitals surrounding the nucleus
How much does each proton or neutron “weigh?” (answer is 1 dalton or 1 atomic mass unit)
1 AMU = 1.7 x 10^-24 grams
What is the definition of atomic number? Mass number? Atomic weight?
Atomic number is the number of protons; mass number is the numer of protons and neutrons; atomic weight is the average mass of all isotopes for the element
Can the number of protons or neutrons for a given element vary? Explain.
Yes, the number of neutrons can vary depending on the number of isotopes. Protons cannot vary, because each element contains a unique number of protons
What is the definition of an isotope?
Variations of an element that contain a differing number of neutrons
What is an orbital? Which orbitals did we discuss in class?
An orbital is the region electrons spend 90% of the time; each orbital can hold up to 2 electrons; the descending order of orbitals are s-p-d
How many electrons can exist in one orbital?
2 electrons
What is an electron shell or energy level?
Series of orbitals filled in a specific sequence; the energy level becomes higher the further it is from the nucleus
What is the “octet rule?”
The rule that each valence shell seeks to fill the shell completely with 8 electrons to stabilize
What is an electron configuration? If I show you one and also give you a periodic table, could you tell me which kind of atom it represents?
It is a demonstration of the number of electrons that fill each electron shell to the maximum of 8 electrons
- What’s the difference between the terms “valence electrons” and “valence of?”
Valence electrons indicate the number of electrons in the valence electron shell; “valence of” indicates the number of bonds the atom can form to fill the valence shell
What is a covalent bond? How many electrons are shared in one covalent bond?
A covalent bond is the interaction of two elements that share at least one pair of electrons in both element’s valence shell; the strongest bond
How is a polar covalent bond different from a non-polar covalent bond?
A polar covalent bond is an unequal sharing of electron pairs in the outer shell that creates a partial positive and partial negative charge; a non polar covalent bond is an equal sharing of electron pairs in the valence shell
What is an ionic bond? How is it different from a covalent bond?
A complete transfer of valence electrons between atoms; it is a type of chemical bond that generates two oppositely charged ions
What is a hydrogen bond?
An electrostatic attraction between two polar groups that occurs when a hydrogen (H) atom covalently bound to a highly electronegative atom such as nitrogen (N), oxygen (O), or fluorine (F); weaker than most ionic attractions because of its partial charges
Describe the properties of one water molecule (describe the water molecule on a molecular level.)
H2O is polar covalently bonded and the electrons in the valence shell are unequally shared; the oxygen molecule is strongly electronegative and the hydrogen molecules are electropositive
What is meant by the statement that “water has polarity?”
Water has polarity means that the oxygen and hydrogen atoms unequally share their valence electrons and are considered polar molecules
Which “end” of a water molecule represents the partial positive charge? Partial negative charge?
The partial positive end is on the hydrogen atoms and the partial negative end is on the oxygen atom.
What is an anion? What is a cation?
An anion is an positively charged ion that has given up at least one electron. A cation is an negatively charged ion that has acquired at least one electron.