Почему местоимение "всё пишется с не раздельно?

Read and say.

1.I am Bob.

I"m Bob.

2.What "s your name ?

What is your name ?

3.He"s12 .

4.I"m in year 8.

5.What is this?

6.My name is Peter .

7.They  are at school. 

8.It"s a ruler.