160 - 2.1 2 3 Flashcards
· What are the basic building blocks of all matter?
Atoms
· Describe the structure of an atom
Composed of three smaller particles: Protons, neutrons and electrons. The nucleus of an atom is made of protons and neutrons. A cloud of electrons surround the nucleus.
· What is the difference between and atom and an element?
Atom - smallest piece of an element that retains the characteristics of an element. Element - substance that cannot be broken down by chemical means into other substances.
Define Protons, including location in an atom
Positively charged particle in an atom’s nucleus
Define Neutrons, including location in an atom
Electrically neutral particle in the atom’s nucleus
Define Electrons, including location in an atom
Negatively charged particle that orbits the atom’s nucleus
· Differentiate an element’s atomic number from mass number.
Atomic number indicates how many protons are in each atom of that element. An atom’s mass number is the total number of protons and neutrons in its nucleus.
What is an isotope?
A different form of a single element. Element will have the same number of protons, but not necessarily the same number of neutrons.
· Differentiate an atom from an ion/ When does an atom become an ion?
An atom becomes an ion when it loses or gains an electron
Define Electronegativity
A measure of an atom’s ability to pull electrons from another atom.
Define Chemical Bond
Attractive force which holds atoms together
Define Molecule
Two or more atoms joined by chemical bonds
Define Compound
Molecule that includes different elements
Define Mixture
combination substances that are not chemically combined
What is a covalent bond?
A bond in which atoms share electrons
· How do atoms interact?
Atoms may donate, steal or share electrons to arrive at the right number, depending on the atom’s electronegativity
· Name and describe the 3 kinds of bonds with examples.
Ionic (sodium chloride), Covalent (water), Hydrogen (between water molecules)
· Why is water essential to life? List and explain the factors that contributes to Water’s life giving properties. 5
Its extraordinary properties make it essential to all organisms.
Factors:
Cohesive and adhesive; water molecules stick together, give surface tension, tendency to form H bonds with other substances.
Solvent: dissolves hydrophilic solutes, ions.
Regulates temperature: H bonds resist temp change. Frozen water expands: less dense, aquatic life survives.
Participates in chemical reactions: photosynthesis, respiration
Define Polarity
Separation of charge into distinct positive and negative regions in a polar covalent molecule. (i.e. water)
Define Hydrophobic
Repelled by water, do not dissolve in or form hydrogen bonds with water
Define Hydrophilic
Attracted to water, polar or charged, readily dissolve in water
Define Solution
solutes dissolved in a solvent
Define Solute
A chemical that dissolves in a solvent forming a solution
Define Solvent
A chemical in which other substances dissolve
Define Cohesion
Attraction of water molecules to one another
Describe a polar covalent bond
Atoms with different electronegativity do not share electrons equally; one atom has a more negative charge, the other is more positive
Describe a non-polar covalent bond
Atoms sharing electrons equally; formed between atoms with identical electronegativity
Describe a hydrogen bond. 4
- -A weak attraction between a highly electronegative atom and a hydrogen atom taking part in a separate polar covalent bond
- -Are not chemical bonds.
- -Stabilize the structures of large biological molecules
- -Account for water’s unique properties.
