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ch11 jamal1
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Question | Answer |
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Ch. 11 & 12 STUDY NOTES | |
Atoms= make up everything | |
Parts of an atom= nucleus (protons & neutrons) | |
Protons= (+) charge (positive charge) | |
Neutron= have no charge | |
Opposites attract= + attracts – vice versa | |
Electrons= (-) charge (negative charge) | |
Mass of electron= is smaller than the mass of protons or neutrons | |
Electron cloud= makes up most of the volume of an atom | |
Electrons, protons, and neutrons= make up the atom (subatomic particles) | |
Element= is a substance that cannot be broken down into a simpler substance by ordinary chemical means | |
Pure substance= matter that has the same composition throughout and cannot be separated into its parts by physical means | |
There are more than 100 different kinds of atoms= (about 90 of the elements are found in nature) | |
Examples or a natural elements= carbon, oxygen, gold, silver, and iron | |
Atom= is the smallest unit of an element that has the properties, or characteristics, of that element | |
Molecule= is a group of two or more atoms held together by very strong chemical bonds | |
A molecule= can be made up of more than one atom of the same element | |
Example= molecule in oxygen gas contains two atoms of oxygen | |
Compound= pure substances made up of two or more different elements that are chemically joined | |
Elements= are always found in the same portion | |
Example= table salt has the chemical formula NaCl | |
This compound= always has exactly one atom of sodium (Na) and one atom of chlorine (Cl) | |
Elements, compounds, and mixtures= are identified and represented by chemical formulas | |
Periodic table of elements= presents and organs information about all the elements | |
Each element= has a box in the periodic table that contains information specific to that element | |
First letter= always capital in box of elements | |
Atomic number= identifies the number of protons in the nucleus of one atom of an element | |
Atomic mass= the weighted average of the masses of all the naturally occurring isotopes of an element | |
The periodic table= is a useful model that can help you understand the properties of elements | |
Horizontal row= in the table is called a period | |
Periods are numbered 1-7 | |
Vertical row= in the table is called a group | |
Groups are numbered 1-18 | |
Periods are numbered 1-7 | |
Metals= more than 75% of the elements in the periodic table are metals | |
Metal properties= metals are usually shiny, malleable, ductile, and are usually slid at room temperature and good conductors of heat and electricity | |
Nonmetals= are elements that are not metals | |
Nonmetal properties= some are gases but the solid ones have these properties, usually dull in appearance, brittle, and poor conductors of heat and electricity | |
Metalloids= substances that have some characteristics of both metals and nonmetals | |
Metalloid properties= semi-conductors | |
Chemical property= characteristic that determines how a substance will interact with other substances during a chemical reaction | |
Observing chemicals= you cannot observe a chemical property of a substance without changing the substance | |
Reactivity= describes how likely an element is to react and form bonds with other elements | |
Ion= is an atom that has a positive or negative charge | |
Ions form= when atoms gain or lose electrons | |
Inert=unable to react chemically | |
Halogens=the most reactive nonmetals | |
Alkali Metals= the elements in group 1 of the periodic table, they are the most reactive metals | |
Alkaline-earth metals= the elements in group 2 of the periodic table, they are reactive but are less reactive than alkaline metals | |
Transition Metals= do not give away electrons as easily as atoms of the groups 1 and 2 metals do, making them less reactive then alkali and alkaline-earth metals | |
Boron Group= one metalloid and four metals, somewhat reactive | |
Carbon Group= one nonmetal, two metalloids and two metals reactivity varies amongst the elements | |
Nitrogen Group= two nonmetals, two metalloids and one metal varies among the elements | |
Oxygen Group= three nonmetals, one metalloid, and one metal reactive | |
Halogens= are very reactive nonmetals because of their atoms need to gain only one electron to have a complete outer level | |
Noble Gases= are unreactive nonmetals | |
Hydrogen= nonmetal that is reactive |