Which two trends increase when one moves across a period from left to right? a) ionization energy and electronegativity b) ionization energy and atomic size c) electronegativity and atomic size d) atomic size and size of cations

Answer is: a) ionization energy and electronegativity.

1) The ionization energy (Ei) is the minimum amount of energy required to remove the valence electron, when element lose electrons, oxidation number of element grows (oxidation process).  

Barium, potassium and arsenic are metals (easily lost valence electrons), chlorine is nonmetal (easily gain electrons).

Alkaline metals (far left in Periodic table) have lowest ionizations energy and easy remove valence electrons (one electron), earth alkaline metals (next right to alkaline metals) have higher ionization energy than alkaline metals, because they have two valence electrons.  

Nonmetals are far right in the main group and they have highest ionization energy, because they have many valence electrons.  

2) Electronegativity (χ) is a chemical property that describes the tendency of an atom to attract a shared pair of electrons towards itself.  

Atoms with higher electronegativity attracts more electrons towards it, electrons are closer to that atom.  

Nonmetals hava higher electronegativity than metals and metalloids.

3) The atomic radius decreases across the periods because an increasing number of protons, because greater attraction between the protons and electrons.

"you start with 15.67 g mgco3-xh2o, when heated and all the water is removed, you are left with 7.58 g mgco3 only.

therefore, you had 15.67 - 7.58 = 8.09g h2o  

moles of each :

7.58g mgco3 = ? moles = 7.58g / 83.4g/mole = 0.09moles  

8 09g h2o = ? moles = 8.09g / 18g/mole = 0.44moles  

molar ratio between the two by dividing both numbers by the smallest number :

0.09 / 0.09 = 1  

0.44 / 0.09 = 4.8  

mgco3-5h2o"