40.0 g ( 1 mole ) --------------- 6.02x10²³ molecules
? ? --------------------------- 2.90x10²² molecules
mass = 2.90x10²² * 40.0 / 6.02x10²³
mass = 1.16x10²⁴ / 6.02x10²³
mass = 1.9269 g
hope this helps!
Answer:
we need to know which atom you're talking about and then you need to say what the mass number is then we can tell how many electrons there are.
(I think)
When a meteroid goes into the atmosphere the friction starts slowing it down and generating heat.
Answer:
At the cathode during the electrolysis of an aqueous solution of magnesium iodide, MgI2 , 2I−(aq) is produced
Explanation:
At cathode, reduction reaction takes place.
The dissociation of MgI2 in aqueous solution is Mg2+(aq) and 2I−(aq)
Here, the Iodine reduces to 2I−(aq) from state of 0 (MgI2) to state of -1 (2I−(aq))
Hence, at the cathode during the electrolysis of an aqueous solution of magnesium iodide, MgI2 , 2I−(aq) is produced
Answer:
Explanation:
An element with atomic number 18 is a noble gas.
The element with atomic number 19 will have one extra electron so it can donate one electron or shed one electron to attain noble gas configuration .
It tends to shed one electron to become positively charged ion . Hence they are electro-positive elements .
Similarly the element with atomic number 17 will have one short electron so it can gain one electron to attain noble gas configuration .
They tend to gain one electron to become negatively charged ion . Hence they are electro-negative elements . They have high electronegativity .