So # of protons is always going to just be the atomic number, which if you look on a periodic table, its the big one in the corner. So you can look that up easy for Li, Ca, and Se.
The numbers tell you the atomic mass over the atomic number.
Since the two particles that give an atom mass (neutrons and protons) both have a mass of about 1 amu, the atomic mass is essentially # of neutrons + number of protons.
So # of neutrons = atomic mass - number of protons.
The number of electrons is the same as the number of protons unless the atom is actually an ion.
If so, then if you had something like Li, it would have 3 electrons (same as # of protons). But if you had Li+, it would only have two. The plus shows that you lost one negative charge (one electron), hence why you have 2. <span />
Answer:
Presence of lone pairs of electrons
Explanation:
According to VSEPR theory, the presence of lone pairs caused increased repulsion of electron pairs on the valence shell of the centeral atom of the molecule. This decreases or distorts the bond angle. The decrease in bond ange depends on the number of lone pairs present on the valence shell of the central atom of the molecule. Ammonia has only one lone pair hence the bond angle is 107°, water has two lone pairs and the bond angle is 104°. Compare this this with the bond angle of 109° in methane which has only bond pairs and no lone pairs.
Answer:
Heat up.
Explanation:
The faster molecules move the warmer an object becomes.
For example boiling water, when you boil water the water molecules will be moving extremely fast.
The slower molecules move, the colder an object is. For example an ice cube. All the molecules are only vibrating.
Hope this helps:)
L
mol/dm³ is measure for molarity
