Science

1.Fill in the gaps:

The reactivity of the alkali metals ________ down the group. Potassium reacts ______vigorously than sodium and lithium is the _________ reactive.

2.Why are the lower elements more reactive?

3.What is the flame colour for a.lithium b. sodium c.potassium

4. Whenever an atom or ion loses electrons it's called ___________

5.Why do alkali metals have similar properties?

6.Write the balanced symbol equation for the reaction between sodium and water.

7. Write the symbol equation for the oxidation of sodium.

1. Increases; more; least

2.The lower an element is in the Periodic Table, the bigger the atom. The bigger the atom, the easier it is for the outer electron to be lost. That is why the lower elements are more reactive. Rubidium and caesium are even more reactive than potassium

3a. red b. orange c. lilac

4.oxidation

5. The alkali metals all have similar properties because when they react they lose an electron and form a positive ion with a stable electronic structure

6.2Na + 2H₂O → 2NaOH + H₂

7. Na → Na⁺ + e^-

force = mass x acceleration

For the same mass: more force causes more acceleration

For the same force: more mass causes less acceleration

For the same acceleration: more mass needs more force

stopping distance = thinking distance + braking distance

Thinking distance can be increased by: greater speed, tiredness, alcohol and drugs, distractions

Braking distance can be increased by: greater speed, poor road conditions (icy, wet), car conditions (bald tyres, poor brakes, full of people)

1a.All the new plants are genetically identical – they will all have the desired characteristics; Organisms that are difficult or slow to breed normally can be reproduced quickly. Some plant varieties do not produce seeds, others have seeds that are dormant for long periods.

b. If a clone is susceptible to disease or changes in environment, then all the clones will be susceptible; It will lead to less variation, and less opportunity to create new varieties in the future

2.Body cell was taken from male sheep A and Egg cell was taken from female sheep B.DNA is extracted from male Sheep A and the nucleus is removed from female sheep B. DNA from Sheep A is fused with egg cell from Sheep B. Fused egg cell develops into embryo which is placed in uterus of foster mother e.g Sheep C. Lamb is a clone of Sheep A.

3. Different combinations of plant hormones are used to make the cells first divide rapidly and then to differentiate the cells into stem, root and leaf cells