The answers here is B) Before, the substance was a gas, later it was a liquid.
Gas particles move freely and away from each other. However, liquid particles move around each other.
Hope this helps! :)(
Answer: the mass number of the daugther atom is 232,
Explanation:
1) Alpha (α) decay is a nuclear reaction in which a nucleus (parent's nucleus) emits an alpha (α) particle and leads to a different atom (daughter atom).
2) The alpha (α) particle is a nucleus of helium atom, i,e, a nucleus with two protons and two neutrons. The symbol used for the α particles is <em>⁴₂He</em>, where the superscript 4 indicates the mass number (2 protons + 2 neutrons = mass number 4), and the subscript 2 indicates the atomic number (number of protons).
3) Then, to determine the mass number of the daughter atom you just need to do a mass number balance:
mass number of the parent atom = mass number of the daugther atom + mass number of the α particle.
The mass number of the radioactive (parent) atom is 90 protons + 142 neutrons = 232.
∴ 232 = x + 4 ⇒ x = 232 - 4 = 228 ← answer.
The full equation may help you to have a wider vision of the problem:
²³²₉₀ X → ⁴₂ He + ²²⁸₈₈ Y
Note this:
- 232 = 4 + 228 (this is a mass number balance)
- 90 = 2 + 88 (this is an atomic number balance)
- X is the parent atom, and Y is the daughter atom
- You can use a periodic table to determine the identity of the unknown atoms (using the atomic numbers).
Answer:
the Bohr model, an electron's position is known precisely because it orbits the nucleus in a fixed path. In the electron cloud model, the electron's position cannot be known precisely. Only its probable location can be known.
<span>Electrons in a nitrogen-phosphorus covalent bond are not shared equally because nitrogen and phosphorus do not have the same electronegativity. The atoms spend more time around the most electronegative atom nitrogen.</span>
The correct answer would be the first option. Material A having a smaller latent heat of fusion would mean that it will take only less energy to phase change into the liquid phase. Latent of heat of fusion is the amount of energy needed of a substance to phase change from solid to liquid or liquid to solid.
