Answer:
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Answer:
Hydrogen
Explanation:
Hydrogen, most abundant in the universe, is the chemical element with atomic number 1, and an atomic mass of 1.00794 amu, the lightest of all known elements. It exists as a diatomic gas (H2).
D.
This happens because in warmer temperatures, the atoms are more active. This increases the pressure because each atom uses up more space as they become more active.
Substance A is ionic because in molten and aqueous solution conduct electricity and dissolves in water. This is because it dissociate in ions and ion conduct electicity and dissolve in polar molecules (water). Ionic bond is very strong (high melting point).
Substance B non polar covalent, because it is not dissolve in polar molecules and has weak intermolecular forces (low melting point).
Substance C is polar covalent because polar molecules have stronger intermolecular forces than non-polar and higher melting points.