<h3>
Answer:</h3>
Lead-205 (Pb-205)
<h3>
Explanation:</h3>
<u>We are given;</u>
We are supposed to identify its product after an alpha decay;
- Polonium-209 has a mass number of 209 and an atomic number of 84.
- When an element undergoes an alpha decay, the mass number decreases by 4 while the atomic number decreases by 2.
- Therefore, when Po-209 undergoes alpha decay it results to the formation of a product with a mass number of 205 and atomic number of 82.
- The product from this decay is Pb-205, because Pb-205 has a mass number of 205 and atomic number 82.
- The equation for the decay is;
²⁰⁹₈₄Po → ²⁰⁵₈₂Pb + ⁴₂He
- Note; An alpha particle is represented by a helium nucleus, ⁴₂He.
Answer: Option (c) is the correct answer.
Explanation:
HF is a weak acid and not a strong acid. This is because fluorine is a highly electronegative atom and when it combines with a hydrogen atom then it will attract the valence electron of hydrogen atom more towards itself.
As a result, it will not dissociates easily to give hydrogen ion. Hence, it acts as a weak acid.
A neutralization reaction is defined as a reaction in which an acid reacts with a base to give salt and water. For example, 
It is true that, spectator ions "appear in the total ionic equation for a reaction, but not in the net ionic equation".
Titration is defined as a process in which concentration of an unknown solution is determined using a solution of known concentration.
Thus, we can conclude that the statement HF, HCl, and HNO3 are all examples of strong acids, is false.
Answer:
CH3CH2CH2Cl
CH3CH2CH2CH2CH2SH
Br2
Explanation:
Dispersion forces increases with increase in relative molecular mass. The specie having the greater relative molecular mass definitely has greater dispersion forces. A rough estimation of the relative molecular masses of the species stated in the answer will reveal this fact.
Answer:
Gravitational force between two objects depends on: a. The weight of the objects c. The mass of each object b. The distance between the objects d. Both b and c Please select the best answer from the choices provided A B C D
✓d
Answer is valence electron, they all have total of 2 valence electron.
remember group number = valence electron
