Hydrogen bonds.
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Ionic bond is formed between positive and negative ions.
Positive ion is known as cation (electropositive metal)
Negative ion is known as anion ( electronegative non-metal)
The bond formed between a metal (positive ion) and non-metal (negative ions) is known as Ionic bond.
Ionic form is formed when one or more electrons from the valence shell of an atom (electropositive metal ) are completely transferred to the valence shell of another atom (electronegative non-metal). Ionic bonding is the complete transfer of valence electron(s) between oppositely charged atoms.
For example: Bond between NaCl(sodium chloride) is an ionic bond in which Na (sodium ) is positive ion(metal) which have +1 charge and Cl (chlorine) is negative ion(non-metal) which have -1 charge and the bond formed between Na+ and Cl- is ionic bond.

Answer:
57.47 grams of sodium is in the sample.
Explanation:
Given that a 100.0-g sample of sodium hydroxide contains sodium, oxygen, and hydrogen, and the sample contains 2.53 g of hydrogen and 40.0 g of oxygen, to determine what mass of sodium is in the sample the following calculation must be performed:
100 - (40 + 2.53) = X
100 - 42.53 = X
57.47 = X
Therefore, 57.47 grams of sodium is in the sample.
Answer:
What best describes how light is produced is transmit & scatter light
Size of a sodium ion is smaller than a sodium atom.