A catalyst
A catalyst can be in many forms
Answer:
a
Explanation:
Because of their valence electron
Carbon, Silicon and germanium has 4 as their valence electron
Explanation:
when an iron bar rust is an example of a chemical change in which a new substance is formed and the change is not easily reversible.for iron to rust moisture and air must be present.while when a substance freezes,it can be easily reversed through melting and no new substance is formed.this change is termed a physical change.
Answer: Ionic radii is half the distance between two ions.
Explanation: from top to bottom down an element group, ionic radius increases. This is because a new electron shell is added as you move down the periodic table.
Might Be wrong not sure :)
Answer:
All objects resist changes to their states of motion.
Explanation:
Sir Issac Newton was an English physicist, mathematician, astronomer and a well known author. Besides, he was a great scientist. Newton discovered many scientific phenomenon and scientific theories in nature.
The most important and famous discoveries of Newton is the Newton's laws of motion. Newtons stated three laws of motion, namely, Newtons 1st law of motion, Newton's 2nd laws of motion and Newton's 3rd law of motion.
According to Newtons's 1st law of motion : A body continues to be in the state of motion or in the state of rest until and unless an external force is applied to it. In other words, all bodies resists changes to the states of their motion or rest.
