Can ions be molecules

Introducing the electron now, before students meet the other sub-atomic particles, can help to embed the idea that the loss of electrons results in a positively charged ion, and may help reduce confusion later on.

Owing to the interweaving of the terms atom, ion and molecule when describing the different particles, it is unsurprising that students get confused. Using games and an element of competition can be helpful to bring some variety to the necessary student practice.

One such game is based on the classic Connect 4 game. You can download instructions, an example grid and game cards below. As the students develop their understanding of chemical bonding further, it is common for students to refer to ionic compounds as molecules or to refer to intermolecular forces when explaining properties of ionic compounds. A molecule is a neutral particle, composed of a set number of atoms bonded together. The particle of the substance is the molecule, rather than the atoms that make up the molecule.

By contrast, ionic compounds are made up of an indeterminate number of ions, in a fixed ratio. The particle of the ionic substance remains the ion. You can further explore the use of chemical models and their limitations in Using molecular models and in the 7 simple rules to for science teaching series.

You can further explore the use of chemical models and their limitations in Using molecular models rsc. Other misconceptions students may hold are discussed in Beyond appearances: Students misconceptions about basic chemical ideas , including that atoms share the properties of the bulk material and that molecules have different properties in different states.

Other misconceptions students may hold are discussed in Beyond appearances: Students misconceptions about basic chemical ideas rsc. At 14—16, students are introduced to sub-atomic particles and how these define the nature of atoms and ions.

Students then go on to study the difference between the nature of the forces that exist between atoms, molecules and ions, which they use to explain the physical properties of ionic and covalent compounds. The resource, Why do atoms form ions allows students to assess their understanding of atoms, ions and ionic compounds and enables the teacher to identify any misconceptions.

The resource, Why do atoms form ions rsc. During lockdown, teachers worked so hard to create engaging remote resources. Scientists dispel the theory that sunlight exposure simply fragments macroplastics that persist in the environment, but what are the implications for the environment? You will also be better equipped to understand many of the important environmental and medical issues that face society. By the end of this chapter, you will be able to describe what happens chemically when a doctor prepares a cast to stabilize a broken bone, and you will know the composition of common substances such as laundry bleach, the active ingredient in baking powder, and the foul-smelling compound responsible for the odor of spoiled fish.

Finally, you will be able to explain the chemical differences among different grades of gasoline. Radioactivity is the emission of energetic particles and rays radiation by some substances. Neutral atoms have the same number of electrons and protons. Atoms of an element that contain different numbers of neutrons are called isotopes. Each isotope of a given element has the same atomic number but a different mass number A , which is the sum of the numbers of protons and neutrons.

Ali, I. New generation adsorbents for water treatment. Aliprandi, A. Punctured two-dimensional sheets for harvesting blue energy. ACS Nano 11, — Allen, B. Carbon nanotube field-effect-transistor-based biosensors. Ang, P. Solution-gated epitaxial graphene as pH sensor. Bai, H. A pH-sensitive graphene oxide composite hydrogel. Berger, C. Electronic confinement and coherence in patterned epitaxial graphene.

Science , — Boukhvalov, D. Modeling of graphite oxide. Butler, S. Progress, challenges, and opportunities in two-dimensional materials beyond graphene. ACS Nano 7, — Cai, S. Pt 74 Ag 26 nanoparticle-decorated ultrathin MoS 2 nanosheets as novel peroxidase mimics for highly selective colorimetric detection of H 2 O 2 and glucose. Nanoscale 8, — Cai, W.

Synthesis and solid-state NMR structural characterization of 13C-labeled graphite oxide. Castellanos-Gomez, A. Optical identification of atomically thin dichalcogenide crystals.

Chen, J. Ionic strength and pH reversible response of visible and near-infrared fluorescence of graphene oxide nanosheets for monitoring the extracellular pH. Cheng, Z. Suspended graphene sensors with improved signal and reduced noise. Nano Lett. Choi, Y. Role of oxygen functional groups in graphene oxide for reversible room-temperature NO 2 sensing. Carbon 91, — Clark, L. Electrode systems for continuous monitoring in cardiovascular surgery.

Cui, Y. Nanowire nanosensors for highly sensitive and selective detection of biological and chemical species. Curreli, M. Real-time, label-free detection of biological entities using nanowire-based FETs. IEEE Trans. Eda, G. Blue photoluminescence from chemically derived graphene oxide. Fan, F. Electrogenerated chemiluminescence of partially oxidized highly oriented pyrolytic graphite surfaces and of graphene oxide nanoparticles. Georgakilas, V. Functionalization of graphene: covalent and non-covalent approaches, derivatives and applications.

Electronic transport properties of individual chemically reduced graphene oxide sheets. Gorbachev, R. Hunting for monolayer boron nitride: optical and Raman signatures.

Small 7, — He, Q. Centimeter-long and large-scale micropatterns of reduced graphene oxide films: fabrication and sensing applications. Acs Nano 4, — Transparent, flexible, all-reduced graphene oxide thin film transistors. ACS Nano 5, — Homola, J. Surface plasmon resonance sensors for detection of chemical and biological species.

Huang, J. A novel glucose sensor based on MoS2 nanosheet functionalized with Ni nanoparticles. Acta , 41— Huang, T. Photostable single-molecule nanoparticle optical biosensors for real-time sensing of single cytokine molecules and their binding reactions. Hummers, W. Preparation of graphitic oxide.

Itti, L. New eye-tracking techniques may revolutionize mental health screening. Neuron 88, — Jeon, J. Microscopic evidence for strong interaction between Pd and graphene oxide that results in metal-decoration-induced reduction of graphene oxide. Jiang, S. Highly sensitive detection of mercury II ions with few-layer molybdenum disulfide. Nano Res. Jung, I. Kang, X. Glucose oxidase—graphene—chitosan modified electrode for direct electrochemistry and glucose sensing.

Kwak, Y. Flexible glucose sensor using CVD-grown graphene-based field effect transistor. Kwon, S. Reversible and irreversible responses of defect-engineered graphene-based electrolyte-gated pH sensors.

ACS Appl. Interfaces 8, — Lei, N. Simple graphene chemiresistors as pH sensors: fabrication and characterization. Li, J. Carbon nanotubes-nanoflake-like SnS 2 nanocomposite for direct electrochemistry of glucose oxidase and glucose sensing.

Li, P. Ultra-sensitive suspended atomically thin-layered black phosphorus mercury sensors. Liao, W. Interfaces 10, — Lima, P. Lin, X. Loan, P. Luo, J. A novel non-enzymatic glucose sensor based on Cu nanoparticle modified graphene sheets electrode.

Acta , 47— Moses, P. Density functional study of the adsorption and van der Waals binding of aromatic and conjugated compounds on the basal plane of MoS 2. Mukherjee, S. A graphene and aptamer based liquid gated FET-like electrochemical biosensor to detect adenosine triphosphate. Novoselov, S. Two-dimensional atomic crystals. Nowogrodzki, A. Speaking in code: how to program by voice. Nature , — Ohno, Y. Label-free biosensors based on aptamer-modified graphene field-effect transistors.

Electrolyte-gated graphene field-effect transistors for detecting pH and protein adsorption. Park, S. Chemical methods for the production of graphenes. Parlak, O.

Structuring Au nanoparticles on two-dimensional MoS 2 nanosheets for electrochemical glucose biosensors. Peng, H. Label-free DNA detection on nanostructured Ag surfaces. ACS Nano 3, — Robinson, J. Reduced graphene oxide molecular sensors. Sarkar, D. MoS2 field-effect transistor for next-generation label-free biosensors.

ACS Nano 8, — Setford, S. Measurement of protein using an electrochemical bi-enzyme sensor. Shadman, A. Monolayer MoS 2 and WSe 2 double gate field effect transistor as super nernst pH sensor and nanobiosensor. Bio Sens. Shahrokhian, S. Lead phthalocyanine as a selective carrier for preparation of a cysteine-selective electrode. Shan, C. Sheng, Z. Electrochemical sensor based on nitrogen doped graphene: simultaneous determination of ascorbic acid, dopamine and uric acid.

Sholl, D. Seven chemical separations to change the world. News , — Sitko, R. Adsorption of divalent metal ions from aqueous solutions using graphene oxide. Dalton Trans. Sofue, Y. Highly sensitive electrical detection of sodium ions based on graphene field-effect transistors.

Sohn, I. Song, Y. Graphene oxide: intrinsic peroxidase catalytic activity and its application to glucose detection. Stankovich, S. Another way to satisfy the octet rule by sharing electrons between atoms to form covalent bonds. These bonds are stronger and much more common than ionic bonds in the molecules of living organisms.

We commonly find covalent bonds in carbon-based organic molecules, such as our DNA and proteins. The bonds may share one, two, or three pairs of electrons, making single, double, and triple bonds, respectively. The more covalent bonds between two atoms, the stronger their connection. Thus, triple bonds are the strongest. The strength of different levels of covalent bonding is one of the main reasons living organisms have a difficult time in acquiring nitrogen for use in constructing their molecules, even though molecular nitrogen, N 2 , is the most abundant gas in the atmosphere.

Molecular nitrogen consists of two nitrogen atoms triple bonded to each other and, as with all molecules, sharing these three pairs of electrons between the two nitrogen atoms allows for filling their outer electron shells, making the molecule more stable than the individual nitrogen atoms.

This strong triple bond makes it difficult for living systems to break apart this nitrogen in order to use it as constituents of proteins and DNA. Forming water molecules provides an example of covalent bonding. Covalent bonds bind the hydrogen and oxygen atoms that combine to form water molecules as Figure shows. The two elements share the electrons to fill the outer shell of each, making both elements more stable.

View this short video to see an animation of ionic and covalent bonding. There are two types of covalent bonds: polar and nonpolar. In a polar covalent bond , Figure shows atoms unequally share the electrons and are attracted more to one nucleus than the other. This partial charge is an important property of water and accounts for many of its characteristics.

Water is a polar molecule, with the hydrogen atoms acquiring a partial positive charge and the oxygen a partial negative charge. Another way of stating this is that the probability of finding a shared electron near an oxygen nucleus is more likely than finding it near a hydrogen nucleus. Hydrogen bonds, which we discuss in detail below, are weak bonds between slightly positively charged hydrogen atoms to slightly negatively charged atoms in other molecules. Since macromolecules often have atoms within them that differ in electronegativity, polar bonds are often present in organic molecules.

Nonpolar covalent bonds form between two atoms of the same element or between different elements that share electrons equally. For example, molecular oxygen O 2 is nonpolar because the electrons distribute equally between the two oxygen atoms. Figure also shows another example of a nonpolar covalent bond—methane CH 4. Carbon has four electrons in its outermost shell and needs four more to fill it.

It obtains these four from four hydrogen atoms, each atom providing one, making a stable outer shell of eight electrons. Carbon and hydrogen do not have the same electronegativity but are similar; thus, nonpolar bonds form.

The hydrogen atoms each need one electron for their outermost shell, which is filled when it contains two electrons. These elements share the electrons equally among the carbons and the hydrogen atoms, creating a nonpolar covalent molecule.

Ionic bonds are not as strong as covalent, which determines their behavior in biological systems. However, not all bonds are ionic or covalent bonds.

Weaker bonds can also form between molecules. Two weak bonds that occur frequently are hydrogen bonds and van der Waals interactions. Without these two types of bonds, life as we know it would not exist. Hydrogen bonds provide many of the critical, life-sustaining properties of water and also stabilize the structures of proteins and DNA, the building block of cells.

Because the hydrogen is slightly positive, it will be attracted to neighboring negative charges. Scientists call this interaction a hydrogen bond. This type of bond is common and occurs regularly between water molecules.

Individual hydrogen bonds are weak and easily broken; however, they occur in very large numbers in water and in organic polymers, creating a major force in combination. Hydrogen bonds are also responsible for zipping together the DNA double helix. Like hydrogen bonds, van der Waals interactions are weak attractions or interactions between molecules. Van der Waals attractions can occur between any two or more molecules and are dependent on slight fluctuations of the electron densities, which are not always symmetrical around an atom.

For these attractions to happen, the molecules need to be very close to one another. Pharmaceutical Chemist Pharmaceutical chemists are responsible for developing new drugs and trying to determine the mode of action of both old and new drugs. They are involved in every step of the drug development process. We can find drugs in the natural environment or we can synthesize them in the laboratory.

In many cases, chemists chemically change potential drugs from nature chemically in the laboratory to make them safer and more effective, and sometimes synthetic versions of drugs substitute for the version we find in nature. Then, the process of approving the drug for human use begins. This involves a series of large-scale experiments using human subjects to ensure the drug is not harmful and effectively treats the condition for which it is intended.

This process often takes several years and requires the participation of physicians and scientists, in addition to chemists, to complete testing and gain approval. An example of a drug that was originally discovered in a living organism is Paclitaxel Taxol , an anti-cancer drug used to treat breast cancer.

This drug was discovered in the bark of the pacific yew tree. Another example is aspirin, originally isolated from willow tree bark. Finding drugs often means testing hundreds of samples of plants, fungi, and other forms of life to see if they contain any biologically active compounds. Sometimes, traditional medicine can give modern medicine clues as to where to find an active compound. For example, mankind has used willow bark to make medicine for thousands of years, dating back to ancient Egypt.

However, it was not until the late s that scientists and pharmaceutical companies purified and marketed the aspirin molecule, acetylsalicylic acid, for human use. Occasionally, drugs developed for one use have unforeseen effects that allow usage in other, unrelated ways. For example, scientists originally developed the drug minoxidil Rogaine to treat high blood pressure. When tested on humans, researchers noticed that individuals taking the drug would grow new hair.

Eventually the pharmaceutical company marketed the drug to men and women with baldness to restore lost hair. Matter is anything that occupies space and has mass. It is comprised of elements. All of the 98 elements that occur naturally have unique qualities that allow them to combine in various ways to create molecules, which in turn combine to form cells, tissues, organ systems, and organisms. Atoms, which consist of protons, neutrons, and electrons, are the smallest units of an element that retain all of the properties of that element.

Electrons can transfer, share, or cause charge disparities between atoms to create bonds, including ionic, covalent, and hydrogen bonds, as well as van der Waals interactions. Figure How many neutrons do carbon and carbon have, respectively? Figure Carbon has six neutrons. Figure An atom may give, take, or share electrons with another atom to achieve a full valence shell, the most stable electron configuration.

Figure Elements in group 1 need to lose one electron to achieve a stable electron configuration. If xenon has an atomic number of 54 and a mass number of , how many neutrons does it have? Potassium has an atomic number of What is its electron configuration? Ionic bonds are created between ions. The electrons are not shared between the atoms, but rather are associated more with one ion than the other.

Ionic bonds are strong bonds, but are weaker than covalent bonds, meaning it takes less energy to break an ionic bond compared with a covalent one.