Periodic Table of elements

Question 1

n / energy level

Answer 1

orbit / shell / ring

Question 2

11 gases:

Answer 2

H₂ (hydrogen)
He (helium)
O₂ (oxygen)
Xe (xenon)
N₂ (nitrogen)
Ar (argon)
Kr (krypton)
Cl₂ (chlorine)
F₂ (fluorine)

Question 3

2 liquids:

Answer 3

Br₂ (bromine)

Hg (mercury)

Question 4

Electro

Answer 4

using electric current

Question 5

Lysis

Answer 5

to split

Question 6

Electrolysis

Answer 6

splitting an element using an electric current

Question 7

Electrolysis of water

Answer 7

Hoffman’s Voltameter

Question 8

Decompose

Answer 8

break down

Question 9

Law of triads

Answer 9

group of 3 elements wih similar cheical properties where the Aᵣ of middle element is approximately equal to average of other two

Question 10

2 ideas of elements the ancient greeks had:

Answer 10

• 4 elements = earth, air, fire and water

- ELEMENTS = basic substance from which all other materials are made

Question 11

2 ideas of elements the Robert Boyle had:

Answer 11

• ELEMENTS = substances that cannot be broken into simpler matierials
• COMPOUNDS = made from combination of elements and could be broken down again into those elements

Question 12

In the modern periodic table, elements…

Answer 12

• are unique
• are arranged in order of increasing atomic number
• are arranged to demonstrate TRENDS in their physical and chemical properties
• that are METALS are on LEFT of STEPS of STAIRS and non-metals on the right

Question 13

In 1800 the ____________ was used to seperate water into H₂ and O₂ = _____________

Answer 13

• Voltaic Pile (Battery)

- Electrolysis

Question 14

3 ideas of elements the Humphrey Davy had:

Answer 14

• developed even more powerful ELECTROCHEMICAL techniques to decompose componds into their elements
• Isolated pure Pottassium from moist Potassium Hydroxide
• Later Isolated Na, Ba, Sr, Ca and Mg

Question 15

3 ideas of elements the Johann Dobreiner had:

Answer 15

• Noticed that Ca, Sr and Ba had similar chemical properties
  ↳The Aᵣ of Sr is approximately half way between that of Ca and Ba
• Develeped the LAW OF TRIADS
  ↳ restricted to certain elements only and was based on Aᵣ but very important
• Other triads: Cl Ca Li S
  Br Sr Na Se
  I Ba K Te

Question 16

3 ideas of elements the John Newland had:

Answer 16

• Developed the LAW OF OCTAVES
• Only worked for 1st 17 elements discovered at the time and no NOBLE GASES discovered yet
• Incorrectly forced elements to fit the pattern -> included Cu and Ag(very unreactive) in the same group as Li, Na and K(very reactive)

Question 17

4 ideas of elements the Mendeleev had:

Answer 17

• Arranged all known elements in order of increasing Aᵣ
• He placed elements with similar properties in the same vertical column
• Left gaps for undiscovered elements and predicted their properties based on others in the group
• Placed certain elements out of order of increasing Aᵣ so they were in their correct group with similar chemical properties e.g. Te and I were reversed

Question 18

4 ideas of elements the Henry Moseley had:

Answer 18

• Used x-rays to discover each atomic nucleus has a UNIQUE positive charge = Atomic Number
• Element = a substance with all of its atoms having the same atomic number
• Dev. a Periodic Table with elemtns arranged in order of increasing atomic no.
• Proved Mendeleev was correct to place T before I
• Moseley’s P.T. = Modern P.T.

Question 19

Table: differences between Mendeleev’s and the modern P.T.

Answer 19

• gaps left / filled as discovered
• noble gasses not included / included
• arranged in increasing atomic mass / number
• Transitition elements mixed / seperate block