Answer: 
is the correct equation for beta decay.
Explanation:
When a beta particle, that is, 
is emitted in a radioactive decay then it is known as beta decay.
Therefore, beta decay of Polonium-218 is as follows.
Therefore, we can conclude that is the correct equation for the given beta decay.
Answer:
A physical change is a change that does not change the chemical properties of the substance and is purely physical.
Explanation:
The appearance of the object of chemical may change but its chemical properties are the same.
For example:
- Ice melting
- Water boiling
- Dissolving salt in water
- Cutting paper
Answer: Transition metal
Explanation: Copper is definitely a transition metal because the Cu2+ ion has an incomplete d level.
Answer:
4.57 × 10⁶ nanometers
Explanation:
In this problem we are asked to convert between two units i.e. a meter into nanometer. In sciences, the different units are used for a same quantity (achieved by multiplying conversion factors) to get rid of very small values and get a readable and intelligible values.
For Example:
In given statement the value of small distance is 4.5 × 10⁻³ meter the real number form of this number is 0.00457. Hence, this number can be converted to a very large number by multiplying it with 10⁹ or 1000000000. Hence,
4.5 × 10⁻³ × 1.0 × 10⁹ = 4.57 × 10⁶
Or,
4.5 × 10⁻³ meters = 4.57 × 10⁶ nanometers
Although the quantity is the same for same units but the number has changed.
