Unit B section 2 Flashcards
What were Alchemists
Magician scientists
Where did the first chemists live?
Middle East
How is steel formed?
Iron with carbon
where was the word: ‘chemistry’ derived
Khemeia
Define Atomos
Indivisible
who discovered a subatomic particle?
J.J Thomson
define brittle
breaks easily
who discovered how to extract iron from rocks?
Hittites
What does khemia mean
Juice of plant
Greek philosopher who discovered ‘atomos’
Democritus
The elements are arranged in order of increasing________
atomic mass
define atomic mass
mass of one atom of an element
how is atomic mass measured
atomic mass unit (amu)
what are the horizontal rows in the periodic table?
period
what are vertical lines in the periodic table
Group/family of elements
groups/families of elements have similar ___________
chemical properties
Define atomic number
How many protons are in the nucleus of one atom of the element
what are metalloids?
Has metal and non metals
Have similar chemical properties
Groups
Gradually change from metal to non metal from left to right
Periods
Where are the most reactive metals in the periodic table
left
Most reactive metals, they react when exposed to air or water
Alkali metals
React when exposed to air or water but their reactivity is still inferior to another group
Alkaline Earth Metals
Most reactive non-metals, can combine with other elements to form new substances
Halogens
Most unreactive elements
Noble gases
Total number of protons,neutrons and electrons in one atom of an element
Atomic mass
Formula for # of neutrons?
Mass # - atomic #
