1) Answer is: developed by transfer of electrons.
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).
2) Answer is: both result in filled valence shells for the atoms involved.
Fluorine form molecule of fluorine F₂ with single nonpolar covalent bond with filled valence shell as closest noble gas neon (Ne).
Fluorine has atomic number 9, it means it has 9 protons and 9 electrons.
Fluorine tends to have eight electrons in outer shell like neon (noble gas) and gains one electron in chemical reaction.
Electron configuration of fluorine: ₉F 1s² 2s² 2p⁵.
Electron configuration of neon: ₁₀Ne 1s² 2s² 2p⁶.
Another example, magnesium fluoride is salt, ionic compound.
Magnesium (Mg) is metal from 2. group of Periodic table of elements and has low ionisation energy and electronegativity, which means it easily lose valence electons (two valence electrons).
Magnesium has atomic number 12, which means it has 12 protons and 12 electrons. It lost two electrons to form magnesium cation (Mg²⁺) with stable electron configuration like closest noble gas neon (Ne) with 10 electrons.
Electron configuration of magnesium ion: ₁₂Mg²⁺ 1s² 2s² 2p⁶.
Fluorine (F) is nonmetal with greatest electronegativity, which means it easily gain electrons.
Fluorine jas atomic number 9, which means it has 9 protons and 9 electrons. It gain one electron to form fluorine anion (F⁻) with stable electron configuration like closest noble gas neon (Ne) with 10 electrons.
Electron configuration of fluorine ion: ₉F⁻ 1s² 2s² 2p⁶.
3) Answer is: molecule made from the covalent bond of 2 atoms of the same type.
Diatomic molecules are molecules made of two atoms.
They can be homonuclear (molecule made of two atoms of the same element) and heteronuclear (molecule made of two different atoms).
For example: nitrogen (N₂), oxygen (O₂), hydrogen (H₂), carbon monoxide (CO), calcium oxide (CaO), hydrogen chloride (HCl), sodium hydride (NaH).
4) Answer is: True.
Carbon (symbol: C) is the main element in organic compounds, found in living things.
There are approximately 10 million carbon-based compounds in living things, for example proteins (enzymes, antibodies), carbohydrates (sugars), lipids (fats, oils) and nucleic acids (deoxyribonucleic acid DNA, ribonucleic acid RNA).
The reason for so many carbon-based compounds is carbon characteristic to form bonds (single, double, triple) with many different elements.
For example, hydrocarbon is an organic compound consisting of hydrogen and carbon.
