Answer:
Explanation:
The first ionization energy varies in a predictable way across the periodic table. The ionization energy decreases from top to bottom in groups, and increases from left to right across a period. Thus, helium has the largest first ionization energy, while francium has one of the lowest.
Answer:
28.9 g
Explanation:
We know that we will need a balanced equation with masses, moles, and molar masses of the compounds involved.
<em>Gather all the information in one place</em> with molar masses above the formulas and masses below them.
: 159.69 28.01
Fe₂O₃ + 3CO ⟶ 2Fe + 3CO₂
Mass/g: 55.0
1. Use the molar mass of Fe₂O₃ to calculate the moles of Fe₂O₃.

2. Use the molar ratio of CO:Fe₂O₃ to calculate the moles of CO.

3.Use the molar mass of CO to calculate the mass of CO.
The atoms undergo chemical changes.
New substances may be a product of the reaction.
Answer is: (3) ionic and molecular.
Ionic compounds are made of ions held together with ionic bonds.
Ionic bond forms when a cation transfers its extra electron to an anion who needs it.
For example compound magnesium chloride (MgCl₂) has ionic bond (the electrostatic attraction between oppositely charged ions).
Magnesium (metal) transfers two electrons (became positive cation) to chlorine (became negative anion).
Molecular compounds are made up of molecules whose atoms are connected with covalent bonds.
Covalent bond is bond between nonmetals.
For example, molecule carbon monoxide CO has covalent bond.
Carbon (C) and oxygen (O) are nonmetals.
Carbon atom and oxygen atom are connected by a triple bond (six shared electrons in three bonding molecular orbitals) that is formed of two covalent bonds and one dative covalent bond.