Structure of the atom Flashcards
Define the periodic table
Grade that arranges all elements
How many elements are there?
118
How are the elements group?
Grouped in similar groups or categories
How are the elements arranged?
In order of increasing atomic number
Define atomic number
Number of protons in the nucleus of one atom of an element
What information does the periodic table give us?
Items and their sub atomic particles. Each element has a symbol, atomic mass and number
What is atomic mass represented by?
A
Define atomic mass
Total number of nucleons in the nucleus
What is the formula to calculate the number of neutrons?
Number of neutrons = A - Z
What is atomic number is represented by?
Z
When do you round off the atom number if it is not whole in the neutrons?
After your calculations
What are groups in the periodic table?
Eighteen groups – vertical
What are periods?
Seven period – horizontal
Why are elements in the same group?
Similar chemical properties
Define strength or brittleness
How easily a substance breaks
Define malleable
Ability of a substance to re-shape without breaking
Define ductile
Ability of substance to be drawn into thin strands
Define melting and boiling points
Temperature at which a solid changes to a liquid
Define electrical conductivity
Ability of a substance you allowed charge to flow through it
Define heat conductivity
Ability of a substance to transfer heat
Define metallic lustre
How shiny (metal) or non-shiny (non-metal) a substance is
Define phase at room temperature
Solid, liquid or gas
What chemical properties do metals have?
- Strong, malleable and ductile
- High melting or boiling points
- Good conductors of heat and electricity
- Mainly solid at room temperature except mercury as it is a liquid
- Metallic lustre
What chemical properties do nonmetals have?
- Brittle
- Low melting or boiling points
- Poor conductors of electricity and heat
- Solid liquid and gas at room temperature
- Doll looking
How do electrons move?
They move in a defined concentric circles or an energy levels
What part of the atom are closest to the nucleus?
Electrons
How many electrons should be placed in the first energy level?
Two electrons
How many electrons move in the first energy level?
The S orbitals
Which energy level has the lowest amount of energy?
The first energy level
Which energy levels have a higher energy?
Electrons in higher levels further away from the nucleus have higher energy
Why is the arrangement of electrons not simple?
Each energy level they are electrons that move on orbitals
Define orbital
Most probable region in which an electron may be found
How many electrons are in the second energy level?
Eight electrons
How do the electrons move in the second energy level?
S (2 e-)
P (6e-)
How many S orbitals and P orbitals are there in the second energy level?
1S orbital
3P orbitals
How many S orbitals and P orbitals are there in the third energy level?
1S orbital
3P orbitals
Which directions to the S and P orbitals go in?
S and P orbitals go in different directions
What determines how an element reacts?
Electrons in the outermost energy level that determine how an element reacts
What is the Aufbau diagram?
Represents the arrangement of electrons
How are the orbital is represented in the Aufbau diagram?
By a block
How are the electrons is represented in the Aufbau diagram?
Arrows
What are the three rules of the Aufbau diagram?
Aufbau principle, Hund’s rule, and Pauli’s exclusion principle
Define the Aufbau principal
An electron her first enter an orbital which is the lowest possible energy
Define Hund’s rule
No pairing of electrons. PX, PY, PZ orbitals before each orbital contains one unpaired electron
What is Pauli’s exclusion principle?
Orbital contains two electrons which must be the opposite spin