Answer:
Explanation:
Use the position of an element in the periodic table to deduce its valence.
The periodic table is a table that groups elements based on their periodic functions. A group is a vertical arrangement of elements. The group number shows the number of elements in the outer shell of the atoms.
The groups runs from 1 to 8. On the periodic table, elements that has more than 4 electrons in their outermost shell will have a valency of 8 less than the number of outermost electrons.
Write formulas for these hydrides without using subscripts, for example XH3. If no hydride forms, write "none".
for group I : NaH, KH,
group II : MgH2, CaH2,
group III: BH3, AlH3
Group 8 do not form hydrides because of their inertness.
What is the formula of the hydride formed by sulfur?
the hydride of sulfur is H₂S
What is the formula of the hydride formed by potassium ?
the hydride of potassium is KH
Answer:
[(x-37.5)/x]*100%
62.5% (assuming the original sample weighs 100.0g)
Explanation:
Let's say that the original sample is x
Mass of I-125 which has decayed: x-37.5
Percentage of decayed mass: [(x-37.5)/x]*100%
Please recheck, for this may not be the correct answer
