In beta decay, a neutron is transformed into a proton via emission of an electron. This means that the total nucleon number remains the same; however, the proton number is increased by one (and the neutron number decreases by one). Therefore, the parent atom must also have mass number 99 but be of one less atomic number.
The atomic number of Tc is 43 and proton number 42 is Mo. Therefore, the answer is:
99Mo
When forming an ion, this sodium atom will lose 1 electron, as it is the easiest way to form a full shell, as opposed to gaining 7 electrons.
C. 6 Valence electrons. Remember that the family that they are in will determine the number of valence electrons that element will have. Sulfur is in family 16 so it will have 6 Valence electrons.
Answer:
1. Fe + H2SO4 = FeSO4 + H2
iron + sulfuric acid = duretter + hydrogen
2. Mg + 2 HNO3 = Mg(NO3)2 + H2
Magnesium + nitric acid = magnesium nitrate +hydrogen
3. Zn + 2 HCl = ZnCl2 + H2
Zinc + hydrogen chloride= zinc chloride+ hydrogen