Answer:
Rn-224 --> Fr-224 + beta
Explanation:
Hi
When an isotope of radon 224 undergoes a radioactive decay by emitting a beta particle, an isotope of francium 224 is obtained.
Remember that the first letter of a chemical symbol is written with a capital letter
.
Radon: Rn
Francium: Fr
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B. compound a material that contains three elements joined in a fixed proportion
Answer:
The strength of the intermolecular forces in isopropyl alcohol are in between water and acetone, but probably closer to acetone because the water took much longer to evaporate. ... Acetone does not participate in hydrogen bonding, so its intermolecular forces are comparatively weaker, and it evaporates most quickly.
Explanation:
Periodic table is the representation of elements in an order
The history of periodic table can be summarized as
a) 1829 : Johann Dobereiner proposed the triad rule. According to him we can classify the elements in a triad where the atomic mass of middle element is average of atomic mass of the near by two atoms.
For example : Li, Na and K is a triad. Where atomic mass of Na is average of atomic mass of K
atomic mass of Na = 7+ 39 / 2 = 23
However, with the further discovery of elements the law was rejected.
b) 1864 : John Newland proposed the law of octave. According to him we can arrange the elements in a set of seven elements where the property of second set of seven elements will resemble the properties of first of seven elements or property will be repeated after seven elements. This was also rejected due to its limited applicability.
c) Meyer : He arranged some 28 elements into six different families based on their atomic masses. The members of each familiy shared some common properties.
d) 1869 : Mendleev : He actually developed a periodic table based on atomic mass of elements. He arranged the elements into groups and periods. He even left space for some undiscovered elements, which were later on discovered.
e) 1916 : Henry Moseley : He finally arranged elements based on their atomic number based on X-ray studies. He proposed the modern periodic law that the periodic properties of elements are due to atomic number of elements.
To determine the number of phosphorus atoms from a given mass, we need to determine the number of moles of the substance by dividing the molar mass which for in this case is equal to 123.88 g/mol for P4. Then, we multiply Avogadro's number. It <span>represents the number of
units in one mole of any substance. This has the value of 6.022 x 10^23 units /
mole.
mole P4 = 158 kg P4 ( 1000 g / 1 kg ) ( 1 mol / 123.88 g ) = 1275.43 mol P4
# of P4 atoms = 1275.43 mol P4 ( 6.022 x 10^23 atoms P4 / 1 mol P4 ) = 7.68x10^26 atoms P4</span>
