Now, what the third law does is it assigns a zero entropy value to all elements that are at zero kelvin. But remember, kelvin or zero Kelvin is attainable. And let's t y well, this formula says that the temperature, in fact, was zero. The zero here would be a denominator. And that's impossible mathematically, because anything over zero is undefined. Okay, now, last two things that we should mention is that entropy is an extensive property.