Chapter 3 Flashcards
chemical symbols
one or two letter abbreviations for names of elements
periodic table
Arrangement of elements
period
horizontal row on the periodic table; there are 7 periods
group
vertical column on the periodic table, elements of the same group have similar properties
representative elements
Group 1,2 and 13-18 (AKA group numbers 1A-8A)
group numbers
1A-8A (from groups 1,2, 13-18)
transition elements
center of periodic table (groups 3-12) (group numbers 3B-2B)
alkali metals
conducting of heat and electricity
boiling and melting point?
group 1A, with the exception of H
soft, shiny metals, good conductors of heat and electricity, have low boiling and melting points
alkaline earth metals
group 2A (2), shiny metals but not as reactive as alkali metals
halogens
group 7A- highly reactive
noble gases
unreactive
metals appearance? melting point? solidity? conduction of heat and electricity?
shiny solids, malleable, good conductors of heat and electricity, melt at higher temperatures than nonmetals, solid at room temperature (exception: Mercury is liquid at room tempertature
Nonmetals appearance? density? solidity? conduction of heat and electricity?
not shiny, ductile or malleable, poor conductors of heat and electricity, low melting points, low density
Metalloids
found at zigzag (exception Aluminum); have characteristics of metals and nonmetals, semiconductors
Atom
smallest particle of an element
John Dalton’s theory of atoms
- All matter is made of atoms
- All atoms of a given element is similar to one another and different from other elements
- Atoms combine to form compounds, all particular compounds contain the same number of atom and same element
- chemical reactions involve rearrangement, separation, combination of atoms, atoms can’t be created or destroyed
what produces images of individual atoms?
scanning tunneling microscopes (stm)
subatomic particles
protons, neutrons, and electrons
Who discovered electrons?
JJ Thompson
Electrons
negatively charged, determines the physical and chemical properties of an element
protons
positively charged particles that are heavier than electrons
What did J.J Thompson and Rutherford discover from the Gold Foil experiment?
the nucleus is positively charged
electrons surround the nucleus and travel undisturbed