Lab Flashcards
physical properties of elements
Metals
- usually shiny or have a metallic luster
- good conductors of heat and electricity
- ductile (can be drawn into a wire)
- malleable (can be molded into a shape)
- if cut can see fresh shiny metal underneath
physical properties of Na and Ca and why? - metal
- some such as Na and Ca may have a white coating of oxide formed by reacting with O2 in air
Physical property of nonmetals
- not good conductors of heat and electricity
- brittle (not ductile)
- appear dull
- not shiny
Periodic Table
- horizontal rows
periods
periodic table
vertical columns
groups
groups of periodic table
- contains elements that have similar physical and chemical properties
- numbered across the top of the chart
elements in group 1
alkali metals
elements in group 2
alkaline earth
elements in group 7
halogens
elements in group 8
noble gases
- elements not very reactive compared to other elements
dark zigzag line that looks like a staircase in periodic table
- separates the metals on the left side from the nonmetals on the right side
subatomic particles
- (there are different kind of atoms for each of the elements)
- atoms are made up of smaller bits of matter called subatomic particles
protons
possitively charged particles
electrons
negatively charged particles
- so small their mass is considered to be negligible compared to the mass of proton or neutron
neutrons
neutral (no charge) particles
nucleus
- in an atom, the protons and neutrons are tightly packed in the tiny center called necleus
atoms
- most of atom is empty space, contains fast-moving electrons
atomic number
equal to number of protons
Z = p+ = e-
mass number of an atom
protons + neutronsº
isotopes
atoms of the same element that differ in the number of neutrons
- have the same number of protons, but different mass numbers
complete symbol of an isotope
mass number (p+ and nº) -> 34 symbol of element ----------> S atomic number (p+) --------> 16
Dmitri Mendeleev
found that the chemical properties of elements tended to recur when the elements were arranged in order of increasing atomic mass
repetition of similar characteristic is called?
periodic behavior
valence electron
- electrons in the highest or outermost energy level
- determine chemical properties of the elements
- if elements are grouped according to number of valence electrons - chemical and physical properties are similar
