Chapter 2 Chemistry Flashcards
What is the difference between an Element and a Compound.
Element: Pure Substance, can’t be broken down by ordinary means
Compound: Two or more elements combined
How many elements are essential to life?
25
What elements make up 96 % of the life elements?
O, C, H, N, P, S (CHONPS) Carbo, Hydrogen, Oxygen, Nitrogen, Phosphorus, Sulfur
What is Atomic Mass?
The number of protons and neutrons. It has decimals b/c there are different forms of the atoms
What is Atomic Mass?
The number of protons and neutrons. It has decimals b/c there are different forms of the atoms
What are an isotopes?
Atoms of the same element w/ dif. # of neutrons
What determines the chemical properties of an atom?
The number of electrons in the outermost shell
What is an ionic bond ?
occurs b/tw atoms when there is a transfer of electrons
What is a positive ion called?
Cation
What is a negative ion called?
anion
What is a Covalent Bond?
when atoms share electrons
Nonpolar Covalent Bond
atoms share electrons equally
Polar Covalent Bond
atoms share have an unequal sharing of electrons due to electronegativity differences
Hydrogen Bond
happens b/tw molecules due to unequal sharing of electrons & it contains a hydrogen atom
Trace Elements
minerals present in living tissue in small amounts
What is matter?
Any substance that has mass and takes up space
Neutron
Subatomic particle found in the nucleus, it has no charge
Proton
Subatomic particle in the nucleus, has a positive charge
Electron
subatomic particle found on atoms shells w/ neg. charge
Energy
ability to exert force that causes displacement of an object
Electron Shells
The outside part of an atom around the nucleus
Molecule
A group of atoms bonded together
potential energy
energy held by an object because of its position relative to other objects
Which has more PE water v. glucose
Glucose b/c more energy is stored in the chem bonds
Which has more PE: Electron 1st or last shell?
Last b/c its farther from the nucleus
What determines the chemical behavior of an atom?
Atomic Number & stability of nucleus
Electronegativity
tendency of an atom in a molecule to attract the shared pair of electrons towards itself.
What is van der Waals forces/interaction ?
Relatively weak electric forces that attract neutral molecules to one another in gases, in liquefied and solidified gases
What is polar molecule
A molecule that is slightly pos. on 1 end and slightly neg. in another end.
How many hydrogen bonds can a single water molecule form?
4 hydrogen bonds
What does the number of valence electrons tell you about the reactivity of an element?
Whether they tend to give up an electron or gain electron during chem. reactions.
How do ions form?
The addition to or the removal of electrons from a neutral atom or molecules.
What is a radioactive isotope? & 1 medical application
An unstable form of a chemical element that releases radiation as it breaks down to become more stable. Carbon-14 is used for various scanning devices
tracers within a living organism to trace what is going on inside the organism at an atomic level; When radioactive isotopes are injected
