Periodic table

Question 1

What was in Mendeleev proposed periodic table

Answer 1

He listed the elements in order of increasing atomic mass (or weight as it was known then) but he was prepared to slightly alter the order of the elements if he felt the properties of the element fitted a different position;

He left gaps for undiscovered elements and predicted the properties of these elements; for example, the properties of germanium, when it was discovered, were very similar to what he had predicted.

Question 2

What is in the modern periodic table

Answer 2

• Elements are arranged in order of atomic number, rather than atomic mass,
• Noble gases are present;
• There are no gaps and there are more elements;
• There is a block of transition metals;
• There is a block of actinides and lathanides.

Question 3

What is in both Mendeleev periodic table and modern periodic table

Answer 3

they both placed the known elements in order

Question 4

What is an element

Answer 4

An element is a substance which consists of only one type of atom. Elements can’t be broken down into anything simpler substance by chemical means.

Question 5

What are elements classified as

Answer 5

Metals and Non-metals

Question 6

What are Metals and what are the properties of them

Answer 6

Metals are to the left of the staircase line on the Periodic Table and are malleable (can be hammered into shape), ductile (can be drawn into wires), sonorous (make a ringing sound when struck), good conductors of heat and electricity and have high melting points

Question 7

What are the gases, liquids and solids in the periodic table

Answer 7

Two elements in the Periodic Table are liquids at room temperature and pressure (mercury and bromine), there are 11 gases including the six noble gases, fluorine, chlorine, hydrogen, oxygen and nitrogen, and the rest of the elements are solid at room temperature and pressure.

Question 8

What is a period

Answer 8

It is an Horizontal row in the periodic table

Question 9

What is a group

Answer 9

It is an vertical column in the periodic table

Question 10

What are group 1 known as

Answer 10

It is a group of reactive metals and the group is known as alkali metals

Question 11

What are group 2 known as

Answer 11

It is a group of reactive metals and the group is known as alkaline-earth metals

Question 12

What are group 7 known as

Answer 12

It is a group of reactive non-metals and the group is known as halogens

Question 13

What are group 8 known as

Answer 13

It is a group of reactive non-metals and the group is known as noble gases

Question 14

What is Group 1 Alkali Metals stored in and why

Answer 14

They are stored under oil to prevent them from reacting with air or water vapor in the air.

Question 15

Properties of group 1 Alkali Metals

Answer 15

are soft and are easily cut with a knife,

are shiny when freshly cut but tarnish (go dull) rapidly when exposed to air;

have low density and the first three - lithium, sodium and potassium are less dense than water, and float on the surface of water;

are grey solids which have relatively low melting points. The melting points decrease as the atoms get bigger going down the group.

Question 16

Reactivity of group 1 Alkali Metals

Answer 16

Reactivity increases down the group

All of the atoms of Group 1 elements have one electron in their outer shell which they lose when the elements react to form a positive ion with full electron shells; as the outer electron is further from the nucleus as Group 1 is descended the elements become more reactive as the outer electron is lost more readily

Question 17

Reaction equation for group 1 Alkali Metals with water

Answer 17

Group 1 metal + water → metal hydroxide + hydrogen

Question 18

Colour of group 7 Halogens

Answer 18

Fluorine → Yellow
Chlorine → yellow-green
Bromine → red-brown
Iodine → grey-black
Astatine → black solid

Question 19

What is the state of the Halogens at room temperature

Answer 19

Fluorine → gas
Chlorine → gas
Bromine → liquid
Iodine → solid
Astatine → solid

Question 20

Iodine sublimes What does that mean

Answer 20

When heated and changes from a grey-black solid to a purple vapor. (changes from solid to gas)

Question 21

Reactivity of group 7 Halogens

Answer 21

Reactivity decreases down the group

All of the atoms of Group 7 (VII) elements have seven electrons in their outer shell and so they gain one electron when the elements react to form a negative ion with a full outer shell.

Further down the group, the atoms have more shells of electrons, so the outermost shell containing electrons is further from the positive attraction of the nucleus. This means the force of attraction between the positive nucleus and an incoming electron decreases and they are less reactive. Also there are more electron shells between the outer electron and the nucleus and these inner electrons shield the outer electron from the attractive power of the nucleus.

Question 22

What is displacement reactions

Answer 22

A more reactive halogen displaces a less reactive halogen from solution.

Chlorine is more reactive than iodine so chlorine can displace it from potassium iodide solution forming iodine and potassium chloride.

Word equation: chlorine + potassium iodide iodine + potassium chloride

Symbol equation: Cl₂ + 2KI → l₂ + 2KCl

ionic equation: Cl₂ + 2I → I₂ +2Cl-

Question 23

Properties of The Transition metals

Answer 23

they have higher melting points;

they have higher density;

they are less reactive with water,

they react and form ions with different charges, but Group 1 metals only form 1+ ions.

Question 24

What colour are some of the Transition metals

Answer 24

copper(II) oxide is black

Copper(II) Carbonate is green

hydrated copper (II) Sulfate is blue

copper (II) Salts are usually blue in solution

Question 25

Properties of the group 0 Noble gases

Answer 25

The noble gases are a group of unreactive non-metals.

Their lack of reactivity is due to the atoms of each element in the group having a full outer shell of electrons.

All of the elements in the group are colourless gases at room temperature and exist as individual atoms.

As the group is descended the boiling points of the elements increase due to the increased strength of the van der Waals’ forces between the atoms.