Y8 - C4 The Periodic Table

Y8 - C4 The Periodic Table

​Learning Objectives

• ​KNOW IT - Know the key words and definitions for this topic

• ​THINK IT - Describe how the modern periodic table was developed

• ​

• GRASP IT - Explain the ​trends in reactivity for Group 1 and 7.

Atoms, Elements and Compounds​

• ​Atoms - The smallest particle (i.e an Oxygen atom)

• ​Elements - A substance made from only one type of atom

• ​Molecule - Two or more atoms bonded together (i.e O₂)

• ​Compounds - Two or more atoms of different types bonded together (ie H₂O)

Multiple Choice

What is the definition for a compound?

• The smallest particle (i.e an Oxygen atom)

• A substance made from only one type of atom

• Two or more atoms bonded together (i.e O₂)

• Two or more atoms of different types bonded together (ie H₂O)

Multiple Choice

What is the definition for an element?

• The smallest particle (i.e an Oxygen atom)

• A substance made from only one type of atom

• Two or more atoms bonded together (i.e O₂)

• Two or more atoms of different types bonded together (ie H₂O)

Multiple Choice

What is the definition for an atom?

• The smallest particle (i.e an Oxygen atom)

• A substance made from only one type of atom

• Two or more atoms bonded together (i.e O₂)

• Two or more atoms of different types bonded together (ie H₂O)

Multiple Choice

What is the definition for a molecule?

• The smallest particle (i.e an Oxygen atom)

• A substance made from only one type of atom

• Two or more atoms bonded together (i.e O₂)

• Two or more atoms of different types bonded together (ie H₂O)

​The development of the periodic table

​Dalton - Ordered elements by atomic mass, used symbols.

​

​Newlands - Ordered elements by atomic mass, Discovered that every 8th element was similar so he put the elements in 8 groups (law of octaves). But he ended up with some of the elements in groups with elements with different properties.

​

​Mendeleev - Ordered elements by atomic mass. Kept the 8 groups but swapped some elements around so they are in the correct groups. Left gaps for undiscovered elements and predicted their properties

​Modern Periodic Table

Multiple Choice

How did Dalton organise the elements in periodic table?

• Atomic numer

• Metals and Non-metals

• Atomic mass

• Reactivity

Poll

Which scientist made the most important discovery?

• Dalton

• Newlands

• Mendeleev

• Dr Ahmed

Multiple Choice

How is the modern day periodic table organised?

• Atomic numer

• Metals and Non-metals

• Atomic mass

• Reactivity

​Physical and Chemical Properties

• ​Physical

  • ​Density

  • ​Boiling / Melting point

  • ​Appearance

  • ​Solubility​

• ​Chemical

  • ​Reactivity

• ​

​Group 1 - The Alkali Metals

• ​React with water to make an alkali and hydrogen gas

• ​Have 1 electron in the outer, therefore want to LOSE 1 electron.

• ​Down the group the atoms get bigger, so the nuclear pull is less

• ​Down the group there is MORE shielding, so the nuclear pull is less

• ​Therefore down the group it is EASIER to LOSE the electron

​Group 7 - The Halogens

• ​Have 7 electron in the outer, therefore want to GAIN 1 electron.

• ​Down the group the atoms get bigger, so the nuclear pull is less

• ​Down the group there is MORE shielding, so the nuclear pull is less

• ​Therefore down the group it is HARDER to GAIN the electron

Multiple Select

Which are properties of metals?

• Sonorous

• Soft

• Dull

• Malleable

Open Ended

Write a physical property of most metals

Multiple Choice

Down a group atoms become

• Bigger

• Smaller

Multiple Choice

Down a group shielding ...

• Increases

• Decreases

Open Ended

Explain why down group 7 elements get less reactive.