Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
17 Cards in this Set
- Front
- Back
|
What is matter?
|
Anything that takes up space and has mass.
|
|
|
What is matter composed of?
|
Elements, or substances that cannot be broken down. There are 92 natural elements.
|
|
|
Living organisms are made of?
|
Primarily 6 elements. CHNOPS
|
|
|
Atomic Structure
|
- elements made of atoms
- atomic symbol - name of atom - periodic table (columns are groups; rows are periods) - elements in groups have similar chemical & phsical characteristics |
|
|
Atomic Structure
|
- atoms composed of
neutron (no charge; proton (+ charge); electron (- charge) - proton & neutron inside nucleus - electron outside nucleus in electron shell |
|
|
Atomic Structure
|
Atomic number = # of protons (= electrons)
Atomic mass # = # of protons + neutrons Letter is chemical symbol |
|
|
What is an ISOTOPE?
|
An atom with the same # of protons but different # of neutrons.
For example, Carbon 12 & Carbon 14 Nucleus of isotope can be unstable & decay decaying isotopes emit radiation |
|
|
Arrangements of ELECTRONS in Atom
|
Electrons encircle nucleus at energy levels called electron Electrons in outer (valence shell) determine chemical reactivity of atoms & are called valence electrons.
|
|
|
Types of Chemical Bonds
|
Groups of bonded atoms form molecule.
Moloecule w/ more than 1 type of element is compound. Different bonds hold molecules & compounds together. |
|
|
IONIC BONDS
|
Formed when + & - ions are attracted to one another.
Ions are charged atoms formed when atoms gain or lose electrons. NaCl |
|
|
COVALENT BONDS
|
Results when two atoms SHARE electrons, thereby completing their valence shells.
H2O |
|
|
Chemical Reactions
|
When molecules/compounds chemically changed called chemical reaction.
Photosynthesis is example. Molecules that participate called reactants. Molecules formed by rxn are products. |
|
|
Structure of Water
|
All organisms 70-90% water.
Unequal shareing of electons in h2o makes h20 polar. Polar h2o molecules are attracted to each other & can form hygrogen bonds. |
|
|
Polar covalent bonds
|
-Atoms have differing electronegativities
-share the electrons unequally. |
|
|
Hydrogen Bonds
|
- forms when hydrogen atom covalently bonded to one electronegative atom is also attracted to another electronegative atom.
- Hydrogen bond is weak |
|
|
Properties of Water
|
1) h2o is a solvent
2) h2o shows cohesion & adhesion 3) h2o has a high surface tension 4) h2o has heat capacity 5) h2o has high heat of vaporization |
|
|
Forms of Water
|
- GAS (hydrogen bonds break)
- LIQUID (H bonds is breaking & reforming) - SOLID (H bond can no longer break, it is fixed)Less dense than liquid, expands as it freezes |
