Google charts not cooperating with me

Google charts not cooperating with me

I have a few issues with google chart:
I want the Y-axis to be from 0 to 20 and a grid-line should occur every 2
points: So I'll have 0,2,4,6,8,10,12, etc and I'm trying to achieve that
with this line of code
'vAxis':{ title: 'Score', titleTextStyle: {color: '#27318B'},
maxValue:20, minValue:0, gridlines: {count:10, color:'#27318B'} }
But it starts at 0 and ends at 22,5 and it shows a grid line at every 2,5.
I don't understand why this is?
I want the width of the graph to be 100%, but when I change it (wether in
html or javascript) I always get a width of 100% but the height gets so
small that nothing is readable anymore, even if specified a height.