UNIT 1 : Atomic Structure Flashcards
what is an element?
An element is the simplest type of chemical substance made up of one type of atom
How are the elements listed?
In a chart called the periodic table in order of increasing atomic number
what are groups in the periodic table?
Groups are a column in the periodic table
what are the different groups in the periodic table?
- Group 1 called Alkali Metals
- Group 7 called Halogens
- Group 8 called Noble gases
- Block between group 2 and 3 are called transition metals
what similarities do elements in the same group have? why?
They show similar chemical properties because elements in the same group have the same number of outer electrons. ( which is same as the group number)
what are all the different ways elements can be classified?
- naturally occurring/ man-made
- solid/ liquid/ gas
- metal/ non-metal
where are all the different classification of elements placed on the periodic table?
_ metals are on left of zig-zag line
- non-metals on right side of zig-zag line
what elements are liquid at room temperature?
mercury and bromine
what are compounds?
different elements which chemically join together to form compounds
what is a mixture?
when substances mix together without a chemical reaction taking place
what do compounds ending in -ide contain?
Contain only two elements
what do compounds ending in -ate -ite contain?
contain more than two elements, one which is oxygen
what are the exceptions for the compound ending rule?
- hydroxide = ‘anything’+hydrogen+oxygen
- cyanide= ‘anything’+ carbon+nitrogen
what is at the centre of an atom?
- core called nucleus
where are protons found?
what charge do they have?
what is their mass?
- nucleus
- one positive charge
- 1 amu
where are neutrons found?
what charge do they have?
what is their mass?
- nucleus
- no charge, neutral
- 1 amu
where are electrons found?
what charge do they have?
what is their mass?
- move outside the nucleus
- one negative charge
- No mass
why are atoms electrically uncharged?
An atom is neutral because the number of protons is equal to the number of electrons
what does the atomic number mean?
number of protons ( also gives number of electrons since equal and opposite charge to protons)
how do u work out mass number?
protons+neutrons
how do u work out number of neutrons?
mass number-protons
how do u work out number of protons?
equal to atomic number
how do you work out the number of electrons?
equal to number of protons ( in a neutral atom)
how do you work out atomic number?
see periodic table
How are electrons arranged?
Arranged in shells ( energy levels)
How many electrons can each shell hold?
- 1st shell = 2 electrons
- 2nd shell = 8 electrons
- 3rd shell = 8 electrons ( for first 20 elements)
what is the nuclide notation?
The atomic number and mass number written with the symbol of the element
35
Cl what do each parts represent?
17
35 = mass number 17 = atomic number cl = symbol of element
what are isotopes?
Atoms with the same atomic number but different mass numbers
what are the similarities and differences of isotopes of one element?
- same atomic number
- same number of protons
- different mass number
- different number of neutrons
what is relative atomic mass?
The average mass of all the atoms of an element
