Lecture 5: Chemistry Review Flashcards
Atomic number (Z)
Number of protons, determines the identity of the atom
What are ions?
Atoms/groups of atoms bonded together with a net charge
Two types of ions
- Cations
- Anions
Cation
Positively charged ion
Anion
Negatively charged ion
Elements contain…
Only 1 type of atom
Compounds contain…
More than one kind of atom in a fixed ratio by mass
What are molecules?
Groups of atoms chemically bonded together into a discrete unit by covalent bonds; neutral charge
What are ionic compounds?
- Contain both positively and negatively charged ions with no identifiable units
- Attracted by charge and are not molecules
Can a substance be both a molecule and an element?
Yes
What is a physical change?
No change in the chemical makeup (i.e.: melting ice)
What is a chemical change?
Always makes a chemically different substance (i.e.: 2H2O —> 2H2 + O2)
What is a physical property?
May be observed/measured without changing the chemical makeup
What are two types of physical properties?
- Intensive
- Extensive
What is an intensive physical property?
Integral to the material, regardless of amount (i.e.: color)
What is an extensive physical property?
-Depends on sample size (i.e.: volume)
What is a chemical property?
Describes the type of chemical changes the material tends to undergo (i.e.: flammable)
Boiling water to steam
Chemical property
Liquid
Intensive physical property
Mass
Extensive physical property
What are substances?
Pure materials that can’t be physically separated into simpler components; can be compounds or elements
Throughout all samples, the chemical and physical properties of substances are ___
Uniform
What is a mixture?
2 or more pure substances
Physical processes can separate the mixture into ___
Simpler substances
Two types of mixtures
- Homogeneous
- Heterogeneous
What is a homogeneous mixture?
Uniform in physical and chemical properties throughout the whole sample (i.e.: normal saline)
What is a heterogeneous mixture?
Distinct phase boundaries where chemical and/or physical properties change (i.e.: emesis)
Protons and neutrons are in the ___
Nucleus
Electrons are located ___
Around the nucleus in cloud-like orbitals
Atoms have ___ properties rather than geometric properties
Wave-like
All atoms have ___ and ___
Protons and electrons
All atoms contain ___ except for ___
Neutrons except for hydrogen
Atomic Number (Z) =
Number of protons, determines identity
Ex: Carbon Z = 6
Neutron number (N) =
Number of neutrons
Mass number (A) =
Z + N
Atomic mass is measured in ___
Amu
Protons and neutrons are ~ ___ amu
~1 amu; leads to mass deficit
The mass number can never be smaller than…
The atomic number
What are isotopes?
Same atomic number, different mass number (diff number of neutrons, same number of protons)
Dalton’s Atomic Theory—Elements are composed of tiny, indivisible particles called ___. All atoms of a given element are…
Atoms; identical and unique to that element