- all atoms in an element are the same, with the same number of protons in the nucleus
-there are 92 naturally occuring, with more created in the lab
Most gas elements are
diatomic (2 atoms of the same element bonded)
Explain 4 things about compounds.
-made of more than 1 kind of atom (2/more elements)
-atoms are bonded in a specific ratio
-compounds may have physical properties completely different the the elements comprising them
-there are bonding rights, so any two elements may not bond
Explain 3 things about mixtures.
-elements, compounds, E & C combined in no ratio and not chemically bonded
-all componets retain their own physical & chmical prop.
-mixtures can be homogeneous or heterogeneous
particles very small and evenly distributed
unevenly distributed like muddy water, pizza, oil, vinegar
a change that does not change composition of a material
a change that changes a materials composition by creating new substances Clues: -release of a gas (bubbling, fizzing, not boiling)
-"magical" color change
-new odors are produced
-"magical" temperature changes
the study of matter
positively charged particles that are located inside the nucleus
neutrally charged particles that are located inside the nucleus
negatively charged particles located outside the nucleus in energy levels or orbitals
Which sub-atomic particle is located outside the nucleus?
in a neutral atom...
each proton has an electron to cancel out the charge
an atoms proton count is given by this
whole number of protons and neutrons in a particular isotope and is always a whole number
weighted average of the masses of the isotopes of a particular element
average atomic mass
samples of the same element with a differing number of neutrons
those created by man that have no isotopes and the avg. atomic mass = mass number
states that an outer shell can only hold 8 electrons