Answer: Massive
Explanation: There are many galaxies out in the universe and it's possible they go on indefinitely. Out of all of these, our solar system is very very tiny. As an analogy, our universe would be like an atom which are the the smallest units of matter. There are many other galaxies that we just haven't been able to discover but they are there.
1kg is 1,000 grams plus .5 is 1.5 kg
Since orbital period depends on how far you are from the sun, planets closer to the sun have a orbital period less than one earth year.
These planets are Mercury and Venus
Answer: There are 7 alpha-particle emissions and 4 beta-particle emissions involved in this series
Explanation:
Alpha Decay: In this process, a heavier nuclei decays into lighter nuclei by releasing alpha particle. The mass number is reduced by 4 units and atomic number is reduced by 2 units.
Beta Decay : It is a type of decay process, in which a proton gets converted to neutron and an electron. This is also known as -decay. In this the mass number remains same but the atomic number is increased by 1.
In radioactive decay the sum of atomic number or mass number of reactants must be equal to the sum of atomic number or mass number of products .

Thus for mass number : 235 = 207+4X
4X= 28
X = 7
Thus for atomic number : 92 = 82+2X-Y
2X- Y = 10
2(7) - Y= 10
14-10 = Y
Y= 4

Thus there are 7 alpha-particle emissions and 4 beta-particle emissions involved in this series
Particle mass charge location
protons 1.673*10 ^ - 27 kg 1.6*10 ^ -19 C in the nucleus
neutrons 1.675*10 ^ - 27 kg 0 in the nucleus
electron 9.11 * 10 ^ - 31 kg -1.6 * 10 ^ - 19 C around the nucleus (orbitals)
Protons and neutrons have almost same masses. Mass of electrons is 1/1840 the mass of the protons.
Protons and electrons have the same magnitud of charge with different sign. Protons are positive and electrons are negative. Neutrons do not have charge.