The number of half -lives that has passed after 105 hours for krypton-79 that has half-life of 35 hours is calculated as below
if 1 half life = 35 hours
what about 105 hours = ? half-lives
= (1 half life x105 hours) /35 hours = 3 half-lives has passed after 105 hours
The answer would be:
D = M/V
D=Density
M= mass
V= volume
Answer:
Yes. The two elements can combine to form different compounds.
Explanation:
Two elements can combine at different ratios.
Consider CO and CO₂. Both are made from carbon and oxygen. However, C and O combine at a 1:1 ratio in CO but at a 1:2 ratio in CO₂. CO is a fuel; it burns in the air. CO₂ does not burn in the air; it is used to put out fires and is found in extinguishers. CO and CO₂ are two distinct compounds.
There are many ways for the elements to combine with each other. As a result, the first twenty elements on the periodic table alone can produce a large number of compounds.
Answer:
Check explanation section.
Explanation:
Yes, that is true. Sodium with chemical symbol Na belongs to the group 1 on the periodic table. Group 1 elements are known as Alkali metals. Other elements in the group are Caesium, lithium, Rubidium, francium and potassium.
Neon belongs to the noble gas of group 8/0.
Sodium is very reactive and and good conductor of electricity. Sodium reacts with water for the production of hydrogen (NB: this reaction is vigorous).
2Na(s) + 2H2O ------------> 2NaOH + H2(g).
They can react with nonmetals such as the halogens. For instance;
Na + Cl2 -------------------------------> 2NaCl.
Sodium is ductile and have low melting point( but high compared to neon).
Neon is not active chemically and it has no odour and no color
