Topic 2 - Metals and Groups of the Periodic Table Flashcards
What elements exist as diatomic molecules?
Hydrogen (H) , Nitrogen (N), Oxygen (O), Fluorine (F), Chlorine (Cl), Iodine (I), and Bromine (Br)
Why do elements in the same group react similarly?
They have the same number of outer electrons, and therefore need to gain/lose the same amount, and so react similarly.
- What are the group 1 elements also known as?
- Why are they known as this?
- The Alkali metals
- They react with water to form alkaline metal hydroxides
What are the reactions with water of:
1. Lithium (Li)
2. Sodium (Na)
3. Potassium (K)
How alkaline are the pH of each of these?
- Floats on water, fizzes (Alkaline)
- Floats on water, melts into a ball, fizzes, moves rapidly on the surface of water (More Alkaline)
- Burns with a lilac flame, melts, moves rapidly on the surface of water (Even more Alkaline)
Therefore, alkaline pH increases as you go down group 1
- What is produced when the Alkali metals react with water?
- Therefore, what is the formula for the reaction?
- Metal hydroxides and Hydrogen
- Metal + Water –> Metal Hydroxide + Hydrogen
The (Metal) Hydroxide solution formed is Alkaline (This can be shown using universal indicator)
e.g. Sodium + Water –> Sodium Hydroxide + Hydrogen
2Na+2H2O –>2NaHO+H2
How is reaction shown using dot and cross diagrams?
First, draw the elements before the reaction, showing the number of electrons in their outer shells. (On the left of the arrow). Use arrows to show the movement of electrons. Then draw the same but after the reaction (After the arrow). Place square brackets around the ions/ reacted elements, and place the charge outside the brackets in the top right. The charge is how many electrons the element needs to gain/lose to get back to normal, indicated using [number]+/-
Why are elements more reactive as you move down group 1?
The outer electrons are further from the nucleus, meaning they have less force of attraction towards the nucleus. Therefore they are easier to lose and the element will react easier.
How are elements arranged in the periodic table?
By Atomic Number (Low to High)
- How do you write electron configurations?
- How do you know what group elements are in based on their electron configuration?
- You write how many electrons are in each shell, e.g. Magnesium would be 2,8,2 (Total number of electrons = atomic number)
- The number of electrons in the outer shell is what group an element is in, e.g. 2,8,2 would be in group 2, and 2,8,7 would be in group 7
- Why are the elements in group 0 unreactive?
- Why are elements in group 1 so reactive?
- They already have a full outer shell, so don’t need to react to gain/lose electrons and get a full outer shell
- They only have one electron in their outer shell, which is easy to lose
What are elements in group 7 known as?
The halogens
What are the state at room temp and colour of:
1. Fluorine (F)
2. Chlorine (Cl)
3. Bromine (Br)
4. Iodine (I)
- Gas, Light Yellow/Green
- Gas, Green
- Liquid (which easily vaporises) Red/Orange liquid and gas
- Solid (Which easily forms vapour) Grey solid - Forms Purple gas
- What are 5 physical properties all halogens have?
- What is the rule for melting and boiling point as you go down the group
- They are all diatomic, have strong covalent bonds, have weak intermolecular forces, low melting + boiling points, and are all poor conductors of heat and electricity.
- Melting and boiling point increase as you go down group 7
- What is the trend of reactivity as you go down group 7?
- Why is this?
- Reactivity decreases as you go down group 7
- The outermost electrons are further from the nucleus as you go down the group, therefore it is harder to attract a new electron (as group 7 elements need to gain 1 electron), as it will be less strongly attracted to the nucleus.
What is the formula for the reactions of:
1. Metal + Oxygen
2. Metal + Water
3. Metal + Acid
- Metal + Oxygen –> Metal Oxide
e.g. Sodium + Oxygen –> Sodium Oxide - Metal + Water –> Metal Hydroxide + Hydrogen
e.g. Sodium + Water –> Sodium Hydroxide + Hydrogen - Metal + Acid –> Salt + Hydrogen
e.g. Sodium + Hydrochloric Acid –> Sodium Chloride + Hydrogen
What is a displacement reaction?
A reaction where a more reactive metal displaces a less reactive metal from a compound.