Atomic structure and the Periodic table 1.14-1.24 Flashcards
Define atom
Atoms consist of a nucleus containing protons and neutrons, surrounded by electrons in shells
Define molecule
More than one atom held together by covalent bonds
What is an atom made up of?
3 subatomic particles - proton, neutrons and electrons
What are the characteristics and location of protons?
Relative charge = +1 (positively charged)
Relative mass = 1
In the middle of the atom in the nucleus
What are the characteristics and location of neutrons?
Relative mass = 1
Relative charge = 0
In the nucleus with protons
What are the characteristics and location of electrons?
Relative mass = 0.0005 - very small mass
Relative charge = -1 (negatively charged)
Move around the nucleus in shells
Size of their orbits determines the size of the atom
What are the numbers of electrons and protons in atoms?
Atoms have no charge overall
Number of electrons = Number of protons
Electron is added or removed the atom is charged and becomes an ion
What does the atomic number tell you?
How many protons there are
What does the mass number tell you?
Total number of protons and neutrons in the atom
Define isotope
Different atomic forms of the same element, which have the same number of protons but different numbers of neutrons
(different mass numbers)
What is relative atomic mass?
How heavy different atoms are compared with the mass of an atom of carbon-12 - average mass of all the isotopes of an element
How do you find the relative atomic mass?
(mass x abundance) + (mass x abundance)/sum of relative abundances
How are elements arranged in the Periodic Table relative to atomic numbers?
In order of increasing atomic number
What does the columns of the periodic table represent?
Groups - the group which an element is in corresponds to the number of electrons in its outer shell
What do the rows of the p.t. represent?
Periods - properties of the elements change as you go along a period
Periods also say how many shells that element has
Why do elements in the same groups have similar properties?
They all have the same number of electrons in their outer shell
How many electrons can be in each of the shells?
1st shell: 2
2nd shell: 8
3rd shell: 8
How do you classify elements as metals or non metals?
Non-metals on right of the table - separated by a zigzag from boron to astatine
Metals on left side of the table
What are the properties of metals oxides?
Basic - neutralise acids
Metal oxides that dissolve will form solutions with a pH of more than 7
What are the properties of non-metals oxides?
Non-metal oxides are acidic - neutralise bases
Dissolve in water to form solutions with a pH of less than 7
What does inert mean?
Don’t react with much
Why do Group 0 (noble gases) elements not react?
