General Chemistry Stuff Flashcards
Definition of Chemistry
the study of matter and the changes it undergoes
Definition of matter
anything that has mass and takes up space
Definition of atoms
submicroscopic particles that are the fundamental “building blocks” of all matter
Physical characteristics of solid
- definite shape
- not easily compressible
- molecules are densely packed
Physical characteristics of liquid
- no definite shape
- not easily compressible
- molecules are loosely packed
Physical characteristics of gas
- no definite shape
- easily compressible
- molecules not packed
An tank of gas becomes “empty” when -
the pressure inside the tank equalizes with the pressure of the atmosphere (even if there is still gas in the tank)
Atomic mass
Made up of the protons and neutrons
The number of protons gives us it’s___ and identifies which ___ it is
atomic number; element
What does changing the number of neutrons of an element do?
change the mass and creates isotopes
What determines the charge of the element?
The electrons
Definition of a molecule
two or more atoms joined together
Definition of a compound
a molecule that contains at least two different elements
What is matter called that consists of two or more pure substances that retain their individual identities?
a mixture
What is a pure substance that can be broken into separate parts called?
a compound
What are chemical properties of matter?
property displayed by a substance caused by a change in it’s composition (flammability, acidity, toxicity)
Where are alkali metals found?
Group 1
Where are alkaline earth metals found?
Group 2
Where are halogens found?
Group 17
Where are noble gasses found?
Group 18
Where are transition metals found?
Group 3-12
What are core electrons?
innermost electrons that occupy the lowest energy levels and are not involved in chemical bonding
What are valence electrons?
outermost electrons that occupy the highest energy level and are involved in chemical bonding
Aufbau principle
an electron occupies the lowest-energy orbital that can receive it
Trends of atomic size on periodic table
increases going down and to the left
Trends of electronegativity on periodic table
decreases going down and to the left
Empirical formula
the simplest whole number ratio of the elements in a compound
Structural formula
the exact number of each type of element and exact manner in which these atoms are bound together (Lewis structure)
Molecular formula
the exact numbers of each type of element found in a compound
Define atomic elements
elements that exist in nature with single atoms as their basic unit (Na, Mg, Ag, Au)
Define molecular elements
elements that exist in nature as molecules (H2, N2, O2, Cl2, Br2, P4)
What is a molecular compound?
composed of two or more non-metals
Melting
Solid–> liquid
Freezing
Liquid–> solid