Ionic bonds are formed between elements where one is ‘happy’ to loose electrons (mostly metals) to attain stable electron configuration while the other is ‘happy’ to accept electrons (mostly non-metals) to achieve a stable electron configuration. The atoms, therefore, becomes charged after the loss/gain of electrons and come together by electrostatic forces.
An example of a compound formed by ionic bonds is NaCl. Na loses its valence electron to Cl to become [Na+][Cl-] while they both attain stable electron configuration of 2.8 & 2.8.8 respectively.
The correct answer is option C) "They are made of metals and nonmetals".
Explanation:
Ionic compounds are molecules that are comprised of two or more elements hold together by electrostatic forces. Ionic compounds are made of metals and nonmetals. For instance, an aluminum ion and a phosphorus ion are examples of a metal and a non metal that can form ionic compounds, respectively. Metals tend to lose electrons when they are in an ionic form, which makes them cations. On the other hand, nonmetals tend to gain electrons, becoming anions when they are in an ionic form.
Answer: All living organisms are classified by their characteristics.
Explanation: Each kingdom includes a set of organisms that share similar characteristics. The organisms in each Kingdom are considered biologically distinct from the others. The six Kingdoms are: Archaebacteria, Eubacteria, Fungi, Protista, Plants and Animals.
Gram positive bacteria survive better in harsh environment
than gram negative bacteria. This is true. Gram-positive bacteria lack an outer
membrane but are surrounded by layers of peptidoglycan (30 sheets chains thicker)
than is found in the gram-negatives with one or two thin sheets. The peptidoglycan layer
acts as the cell wall's backbone, offering strength to the cell wall and
protects them in harsh environment.