Answer:
The only thing that can scratch Corundum is diamond.
Explanation:
We refer to the Mohs Hardness Scale for the hardness levels. We can see that Corundum is a level 9 which is the second highest so at a level 10 we see diamond, therefore diamond is the only thing that can scratch Corundum.
nebular hypothesis
The most widely accepted theory of planetary formation, known as the nebular hypothesis, maintains that 4.6 billion years ago, the Solar System formed from the gravitational collapse of a giant molecular cloud which was light years across. Several stars, including the Sun, formed within the collapsing cloud.
answer: it increases from left to right
explanation:
the electronegativity of atoms increases from left to right across a period in the periodic table; it also decreases as you move from top to bottom down a group in the periodic table
