Answer:
option D
Explanation:
first quantum number of a 2s2
n = 2
second quantum number of a 2s2
l = 0 to n-1
l = 0, 1
For s orbital
l = 0
third quantum number of a 2s2
ml = - l to +l
ml = 0
fourth quantum number of a 2s2 electron be
?½ = spin down
½ = spin up
2s2 has 2 electrons 1 spin down and 1 spin up (starts with spin down)
ms = +1/2
The elements that form anions will have the electronic configuration similar to the noble gas that is in their period and those that form cations will have a configuration similar to that of the noble gas in the previous period.
He: Be
Ne: F, Al
Ar: Ca, P
Kr: Rb, Se

If every oxygen ion is combined with an aluminium ion has a charge of -2,the charge of each aluminum ion would be -3.
Uncharged Aluminum atom must need to lose it's electrons,in order to form the bond with oxygen which has vacant orbitals
ion
atom that has a positive or negative charge because it lost or gained one or more electrons
chemical bond
the attractive force that holds atoms or ions together
ionic bond
a chemical bond in which one atom loses an electron and the other atom gains electrons to form ions
chemical formula
a combination of chemical symbols and numbers to represent a substance
covalent bond
bond formed by the sharing of electrons between atoms
Answer:
The lung
Explanation:
The model of the respiratory system made by Megan consists of two balloons. The first balloon stretched across the bottom of the bottle represents the diaphragm which contracts and relaxes to allow air in and out of the lungs. The balloon inside the bottle represents one lung.
Breathing in causes the balloon inside the bottle to be filled with air. This is preceded by the expansion of the diaphragm which makes the lungs to be filled with air. Breathing out causes a contraction of the diaphragm thus making the lungs to let out air.
There are 30 protons and 39 neutrons in the nucleus.
This must me the isotope of an element with an atomic mass close to 69 u.
The only candidates are Zn and Ga.
Zn has a zinc-69 isotope with mass 68.926 u.
Ga has a gallium -69 isotope with mass 68.925 u.
The isotope is probably

.
It has 30 protons and 39 neutrons.