Presentation is loading. Please wait.

Presentation is loading. Please wait.

Matter. Origins of the Idea Democritus (~400 BCE) –Matter is composed of atoms –Atoms are eternal, invisible, indivisible, and incompressible Greeks believed.

Similar presentations


Presentation on theme: "Matter. Origins of the Idea Democritus (~400 BCE) –Matter is composed of atoms –Atoms are eternal, invisible, indivisible, and incompressible Greeks believed."— Presentation transcript:

1 Matter

2 Origins of the Idea Democritus (~400 BCE) –Matter is composed of atoms –Atoms are eternal, invisible, indivisible, and incompressible Greeks believed in 3 phases or states of matter –Solid, liquid, gas –We now add plasma as the fourth phase

3 Matter in the Universe 99% of the known matter in the universe is Hydrogen and Helium The majority of the known matter is in the form of a plasma in stellar interiors The average density of the known matter in the universe is such that 1 gram would occupy a volume 30 x that of Earth The location and characteristics of most of the matter in the universe is unknown – dark matter

4 Antimatter A matter particle and an antimatter particle are the same with the exception of charge and magnetic properties (which are opposite). Naturally formed and man-made. When matter and antimatter particles collide, they annihilate each other.

5 Elements Fundamental forms of matter Cant be broken apart by normal means 92 occur naturally on Earth They are the same everywhere

6

7 What Are Atoms? Smallest particles that retain the distinguishing physical and chemical properties of an element Made up of subatomic particles: –Protons (+) –Electrons (-) –Neutrons (no charge)

8 HydrogenHelium electron proton neutron Examples of Atoms

9 Chemical Bonds, Molecules, & Compounds Bond is union between electron structures of atoms Atoms bond to form molecules Molecules may contain atoms of only one element - O 2 Molecules of compounds contain more than one element - H 2 O

10 Atomic Number Number of protons All atoms of an element have the same atomic number Atomic number of hydrogen = 1 Atomic number of carbon = 6 6 C 12 6 C 13 6 C 14

11 Mass Number Number of protons + Number of neutrons Isotopes vary in mass number 6 C 12 6 C 13 6 C 14

12 Isotopes Atoms of an element with different numbers of neutrons (different mass numbers) Carbon 12 has 6 protons, 6 neutrons Carbon 14 has 6 protons, 8 neutrons 6 C 12 6 C 13 6 C 14

13 Chemical Origins Most chemical elements were created after the Big Bang in subsequent generations of stars. Nucleosynthesis: primordial (H, He, Li) stellar (He -> Fe) explosive (Co -> …)

14 Radioisotopes - Radioactivity Have an unstable nucleus that emits energy and particles particles – 2 protons and 2 neutrons particles – an electron rays – a high energy photon Radioactive decay transforms radioisotope into a different element Decay occurs at a fixed rate Because decay happens at a fixed rate, you can use it for age dating! (C 14 has a half-life of 5,700 years.)

15 The Age of the Solar System Ages of rocks can be measured through radioactive dating: Measure abundance of a radioactively decaying element to find the time since formation of the rock Dating of rocks on Earth, on the Moon, and meteorites all give ages of ~ 4.6 billion years.


Download ppt "Matter. Origins of the Idea Democritus (~400 BCE) –Matter is composed of atoms –Atoms are eternal, invisible, indivisible, and incompressible Greeks believed."

Similar presentations


Ads by Google