Please give formulas of how you solved I only need help on a but if you can do all that I would appreciate that.

3.1 moles of ammonia

18.67× 10²³ molecules

Mass = 52.7 g

Explanation:

Given data:

Number of atoms of hydrogen = 5.68×10²⁴ atoms

A) Number of molecules of ammonia = ?

Solution:

First of all we will calculate the number of moles of hydrogen.

1 mole = 6.022× 10²³ atoms

5.68×10²⁴ atoms × 1 mol / 6.022× 10²³ atoms

0.94×10¹ mol

9.4 moles of hydrogen

Moles of ammonia:

3 moles of hydrogen are present in one mole of ammonia.

9.4 moles of hydrogen = 1/3×9.4 =

3.1 moles of ammonia

Number of molecules of ammonia:

1 mole contain 6.022× 10²³ molecules.

3.1 mol × 6.022× 10²³ molecules / 1 mol

18.67× 10²³ molecules

c) Mass of sample = ?

Mass = number of moles × molar mass

Mass = 3.1 moles × 17 g/mol

Mass = 52.7 g

assuming that your periodic table has eighteen columns, you should highlight   the four elements in the third column from the left of the table.

neutral atoms of elements after calcium contain d electrons. the energy of d orbitals of a particular main shell lies between the energy of the s and p orbitals of the next main shell. for example, electrons in the have energy higher than those in the orbital while lower than those of the orbital.

by the aufbau principle, electrons fill orbitals one at a time, starting from those of the lowest energy. the orbital is therefore filled right after orbitals and before orbitals.  

potassium has electron configuration and calcium . the s orbital of a main shell holds a maximum of two electrons. the next element would thus have the electron configuration and satisfy the requirements.

a neutral atom of the element contains three electrons on top of the most recent noble gas element. it should thus be placed in the third column of the periodic table. both scandium and yttrium would satisfy the conditions. an aufbau diagram indicates that the 4f orbital is filled before the 5d. however, it appears that exceptions exists for both lanthanum and actinium. neutral atoms of the two d-block elements also demonstrate the and should be highlighted as well.

it takes on an electronical energy