Answer:
A velocity-time graph shows how velocity changes over time. The sprinter's velocity increases for the first 4 seconds of the race, it remains constant for the next 3 seconds, and it decreases during the last 3 seconds after she crosses the finish line.
Here we have to get the symbol of the selenium ion having two extra electrons.
The symbol of the selenium ion with two extra electrons is
.
The number of electrons present in selenium is 34. The electronic configuration of selenium (Se) is 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p⁴.
Now we can see that there are 4 electrons in p-orbital. The p-orbital can take maximum 6 electrons thus there is two vacant space in 4p orbital for selenium. If we add two electrons then the total number of electrons will be 36. The electronic configuration can be written as:
[Se²⁻] = 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p⁶.
The two negative charge on selenium makes it an anion as one electron always posses one unit negative charge. Thus for the incorporation of the two electrons there will be accumulation of two negative charge on the selenium atom and it will be expressed as Se²⁻.
LiCl
because Li loses 1 electron ==> Li+
and Cl gains 1 electron ==> Cl-
Li+ Cl-
we use the criss cross rule
===> LiCl
Atoms and element do relate with each other.
<h3><u>Explanation:</u></h3>
Atoms are defined as the smallest particle of an element which cannot be divided further keeping its physical and chemical properties intact, and they take part in a chemical reaction.
Elements are defined as the substances that are components of matter and cannot be further divided into simpler substances.
AMU or the Atomic mass unit is defined as a unit that is used to express atomic mass and is equal to mass of a hydrogen ion.
Elements are actually formed of atoms that are present in nature and atoms do form elements and even compounds. So they are inter related with each other.
Answer:
B. Mixture
because air,sea water and alloy are example of Mixture