Chem Flashcards
(20 cards)
What charge does a proton and electron have?
Positive negative
Who created the atomic theory?
Democritus originally had the idea, but John dalton proved it
How many electrons in the first shell? Then so on?
2 then 8
What is the structure of an atom?
Atom: shells- contains electrons, nucleus- contains protons and neutrons.
What is the mass number?
Protons + neutrons
What is a chemical reaction?
When you make new chemicals
How do you know a chemical reaction has taken place?
Change in smell, colour, temp, light,
Why do we use word equations?
To express change of a chemical when you modify it
Example: magnesium + oxygen
What are they?
Reactants
Magnesium + oxygen ( => magnesium oxide)
What is the left part of the equation called?
Products
How can you tell two substances have been put together?
The second word ends in oxide
What is law of conservation mass?
Atoms of an object cannot be destroyed nor created, but can be moved around and changed into different particles.
Law of constant proportions?
A compound always forms from a fixed ratio of its elements example: water as a compound will always form from the same ratio of hydrogen and oxygen.
What is the 3 different radiation levels
Alpha
Beta
Gamma
What does alpha go through?
Beta?
Gamma?
Alpha - paper
Beta- aluminium
Gamma- lead
What is an isotope?
Atoms of the same element with a different mass number same number of protons though
What is a radio isotope:
A version of a chemical element that has an unstable nucleus and emits radiation during its decay to a stable form. Radioisotopes have important uses in medical diagnosis, treatment, and research.
What are endo and Exo thermic reactions?
Exothermic- when a reaction releases heat.
Endothermic- when a reaction absorbed heat.
What is carbon dating used for?
Carbon dating is when carbon 14 levels drop when something dies and that is useful because scientist can measure the c14 to work out the age of an organism.
What is an atomic number?
Number of protons in an element
