Standard 1.1 Common Origins

All matter in the universe has….. Common Origins Therefore, all matter in the universe and on earth is composed of… The same type of elements

So I would expect to find the same elements that exist on earth also in the stars, sun, other planets etc.

The most abundant element in the universe is….. Hydrogen

At first the only elements were hydrogen and helium. Fusion Reactions create the heavier elements

Basically- Fusion of lighter elements formed heavier elements.

The most common element in the universe is hydrogen, and the heavier elements are less common. The earth has more of the heavier elements in its crust than the universe does.

Hubble Hubble was an astronomer who discovered that our universe is expanding. Billions of years ago many believe a “big bang” gave rise to this expanding universe.

Scientists in the Bell laboratory in the 1965 detected “noise” from space in a radio telescope The noise remained constant no matter which direction they scanned. They suspected that it came from bird droppings on the antenna, but after a careful cleaning the noise remained. They discoved waves in space (specifically microwaves)

What important discovery did they make that supports the Big Bang theory? They accidentally discovered radiation leftover from the Big Bang.

Supporting this theory The Big Bang Theory describes the formation of the matter in the universe. Why do scientists support this theory? Evidence from starlight shows that the universe is still expanding.

How do we see what elements are in the stars? by studying the atomic line spectra in the star’s light.

Helium was discovered on the sun in 1868, almost 30 years before it was discovered here on the earth. How could that be possible? Investigation of light from the sun revealed a spectrum not yet found in known elements.

Standard 1.2 Atomic Models and their limitations.

Dalton – atomic theory Atom is small and indivisible, All atoms of an element are identical Atoms can be rearranged -> compounds and chemical reactions Atoms of any one element are different from those of another element

2. Thompson Also called– plumb pudding –

Thompson’s experiment involved the Cathode Ray Discovered the electron. Mass 0, charge -1

Rutherfords experiment is called: Gold foil experiment A beam of alpha particles is shot at gold foil, most of the beam goes all the way through, but some of the beam is deflected.

2. Rutherford model Most of an atom’s mass in the center (nucleus) and is positively charged Atoms are mostly empty Space

3. Bohr Model Electron’s orbit the nucleus

4. The currently agreed upon model Quantum mechanical model Electrons exist in a cloud, within energy levels and travel in waves, Also called the mathematical model because it involves probabilities when trying to figure out where the electron is.

Proton, neutron and electron – what is the mass, charge and where located? Nucleus Protons +1 charge Mass number of 1 Neutrons Neutral charge Mass number of 1 Electron cloud Electrons -1 charge Mass number of 0 Number of electrons = number of protons

How do you identify an atom? The atomic number What is this? The number of protons

What are these elements and what are there atomic masses and there molar masses?

Switch to over head Molar mass Grams to moles and moles to grams Do the ones in your packet.

Relate the mass and number of atoms to the gram-sized quantities of matter in a mole. Average atomic mass = One mole Which = 6.02 x atoms / mole

Switch to overhead Do the ones in your packet

Standard 1.3 Correlate atomic structure and the physical and chemical properties of an element to the position of the element on the periodic table.

Similar column/Group/family Similar properties Because They have the same number of valence electrons

Mass number Atomic number Aluminum with 13 protons & 14 neutrons Can also be written as Al-27 Symbols – With atomic number and mass number

Mass number The number of Protons + neutrons. The atomic number Number of protons The number of protons equals the number of electrons in a neutral atom.

Isotopes Atoms that have the same number of protons but different number of neutrons

How many protons, neutrons and electrons in Neon isotopes? Ne – 20 Ne – 21 Ne - 22 All have 10 protons and 10 electrons 10 Neutrons 12 Neutrons 11 Neutrons

Isotopes – You do How many protons, neutrons and electrons in Oxygen – 16 Oxygen – 18 Oxygen - 19

Isotopes are chemically alike because They have the same number of protons and electrons.

Periodic Table - stuff

First periodic table Dmitrii Mendeleev Organized by atomic mass Current one is organized by? Atomic number

Metals Lose electrons (+ charge) cations, conductive (heat and electricity), malleable, ductile luster

Metals Metals get more reactive as you move to the left and down a group

Nonmetals Gain electrons (-charge) anions Brittle Insulators Non conductors

Nonmetals Non metals – More reactive up and to the right

Metalloids Properties of both metals and non metals Semi-coductors