Answer:
d. 10
Explanation:
The 24 means the atomic mass and twelve means the number of electrons. You subtract the number of electrons from the atomic mass. 24-12=12
Then, since there's +2, you subtract 2 from 12 which equals 10 which means there are 10 electrons now.
The confusing thing is that + means subtract and - means add here.
Hope this helps.
Explanation:
Physical changes are the changes that does not lead to any change in chemical composition of a substance.
For example, mass, density, volume are all physical changes.
On the other hand, a change that leads to formation of a new compound by changing the chemical composition of reactants or combining atoms is known as a chemical change.
For example, combustion, toxicity, reactivity etc are all chemical changes.
Therefore, given changes are identified as follows.
- Coal burning : It is a combustion reaction. Hence, it is a chemical change.
- Ice melting : Physical state of water changes from solid to liquid. Hence, it is a physical change.
- mixing chocolate syrup with milk : No new compound is forming as there is no chemical reaction occurring. Hence, it is also a physical change.
- explosion of a firecracker : It shows reactivity of fire cracker. Hence, it is a chemical reaction.
- magnetizing of a screwdriver : It shows physical attraction between the magnet and screwdriver. Hence, it is a physical change.
Answer:
1L=1000mL
1000mL+300mL=1300mL
so the answer is d.1300mL
Explanation:
The reactivity of a metal is determined by how tightly the metal holds onto the electrons in the outermost energy levels (valence electrons)
