Atoms, elements, and the periodic table Flashcards
Element
a sample of matter made of only one kind of atom. The number of protons determines the identity of the element.
Atomic #
Tells the number of protons in the nucleus of each atom. The Periodic Table organizes elements based on their atomic number ( # of protons).
Atomic Mass
Tells the mass of an atom
Chemical symbol
abbreviations used in chemistry for chemical elements.
Element groups/families
The vertical columns on the periodic table. Elements in the same group or family share chemical properties.
Element periods
The rows on the Periodic Table.
Average atomic mass
is the weighted average of the masses of an elements isotopes. Tells you which isotope is the most common on earth.
Isotope
means “same place”. Atoms of the same element that have different number of neutrons.
Proton
Mass: 1 a.m.u
Charge: Positive
Location: nucleus
Neutron
Mass: 1 a.m.u
Charge: neutral
Location: nucleus
Electron
Mass: 0 a.m.u
Charge: negative
Location: electron cloud
What do atoms really look like?
- Discovery of the nucleus
- The nucleus is positively charged
- Most of the mass is concentrated in the nucleus.
- The nucleus is EXTREMELY small compared to the atom as a whole
- The atom is mostly empty space occupied by the electron cloud.
Metal
- Can be bent and shaped
- Good conductors of heat and electricity
- Solid at room temperature (except mercury)
- Shiny
- Left side of the periodic table
- most elements are metals
- Example: Iron
Nonmetals
- dull solids (not shiny)
- Poor conductors of heat + electricity
- at room temperature, the are either gases, or brittle solids
- right side of periodic table
- Essential to the chemistry of life ( 97% of your body)
- example: oxygen
metalloids
- all solid at room temperature
- Have characteristics of both metals and nonmetals
- semiconductors
- used in electronic devices
- make up the stair step liner of the periodic table (between metals and nonmetals)
- example: Silicon
