waht does amu stand for, what is the amu of H and on the bottom of the periodic table is two lines of elements

Question

i need the answers fast plz

Answer 1

amu stands for atomic mass unit which is a measure of atomic weight (specifically mass). The amu of hydrogen is about 1.008.

The two lines at the bottom of the table are the Lanthanide and Actinide series of rare earth metals.

Answer 2

amu stands for atomic mass unit.
The amu for H is rounded off to 1 amu
The bottom 2 rows which are separated are the rare earth metals.
They are the Lanthanides , row 6 and Actinides, row 7.
They are separated so the periodic table does not have to be spread out wider. They fit in the regular table after Ba, number 56(Lanthanum is 57)and after Ra, number 88 (actinium is 89)
You will note that Lutetinium number 71 follows Ytterbium at 70 and Lawrencium, nmber 103 follows Nobelium at 102.
Man has now made elements almost through 118. Names have not been selected for al of them.

Answer 3

amu = atomic mass unit and is defined as 1/12th of the mass of a carbon-12 isotope.

Hydrogen's mass is 1.0079 amu

At the bottom the periodic table are two groups of elements referred to as "rare earth" elements. These elements belong in the 6th and 7th rows of the periodic table but are taken out and written below the table simple to make the table shorter. That way we can fit wall charts on the wall and note-book sized charts in our notebooks.

Answer 4

amu = atomic mass unit... it is designated by 1/12 of the mass of a carbon-12 isotop (there is also a carbon 13, etc.)