<span>The number of valence electrons. :) have a good day </span>
Answer: D. 4,6,4
Explanation:
The valence electron is the electron found in the outermost shell of an atom, and participates in bond formation.
For the following element, the valence electron can be noticed when we write the electronic configuration of each element.
Silicon = 1s2 2s2 2P6 3s2 3p2
Sulphur = 1s2 2s2 2P6 3s2 3p4
Germanium = 1s2 2s2 2P6 3s2 3p6 3d10 4s2 4p2
Answer is: no reaction occurs.
No reaction occurs because magnesium (Mg) is less reactive than sodium (Na). Sodium is higher in activity series of metals and can not be reduced. <span> Metal X will replace another metal Y in a solution if X is higher in the activity series. </span>
Answer:
B
Explanation:
since isotopeA has bigger mass number
Radioactive decay => C = Co { e ^ (- kt) |
Data:
Co = 2.00 mg
C = 0.25 mg
t = 4 hr 39 min
Time conversion: 4 hr 39 min = 4.65 hr
1) Replace the data in the equation to find k
C = Co { e ^ (-kt) } => C / Co = e ^ (-kt) => -kt = ln { C / Co} => kt = ln {Co / C}
=> k = ln {Co / C} / t = ln {2.00mg / 0.25mg} / 4.65 hr = 0.44719
2) Use C / Co = 1/2 to find the hallf-life
C / Co = e ^ (-kt) => -kt = ln (C / Co)
=> -kt = ln (1/2) => kt = ln(2) => t = ln (2) / k
t = ln(2) / 0.44719 = 1.55 hr.
Answer: 1.55 hr
