Why does `{foo: 1}` evaluate to `1` in the console, and `{foo: 1, bar: 2}` results in an error?

Question

I knew that {} is either an object or a block of code, but today my co-worker asked me why {foo: 1} works when entered into the console, but

Answer 1

{} not block always, you can make an object with it (JSON style) for example

var objectName = {
    propertyName:"Fiat", 
    model:500, 
    color:"white",
    methodName:function(a) {
        return a;
    }
};

objectName.methodName('aa');

objectName.propertyName

objectName[propertyName]

and they're blocks

if(...){ .. }
while(...) { ... }
try(..) { ...} catch  { ...}