How does molecule differ from an atom

When atoms of some different elements combine, a molecule of a compound can form, eg H 2 O. How to teach elements and compounds , in the 11—14 series, describes different strategies for teaching elements and compounds and the common misconceptions students may hold. How to teach elements and compounds rsc. Particle diagrams can be used to help the students visualise the difference between an atom, a molecule of an element and a molecule of a compound.

In fact even Dalton in the s proposed a series of diagrams to represent the elements and compounds known at the time. Use of colour helps to distinguish between the atom types further.

Venn diagrams help students organise their understanding of the different particle types, as described in Atoms, elements, molecules, compounds and mixtures. In fact even Dalton in the s proposed a series of diagrams to represent the elements and compounds known at the time Figure 1. Venn diagrams help students organise their understanding of the different particle types, as described in Atoms, elements, molecules, compounds and mixtures rsc.

An atom or a molecule can lose or gain electron s to form an ion. At this level students only need to know that an ion is a positively or negatively charged particle. However it may be worth introducing students to the electron at this point. This latter point is something students often struggle with later on in their studies. 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.

But when it comes to an atom vs. Now the only question is why? To know the answer to that question, you need to look at the structure of an atom. An atom is the smallest unit of matter. While there are other fun subatomic particle names thrown in there, those are the three most important ones. Here is where it gets interesting. A molecule is made up of atoms bonded together. So, while an atom is its own separate entity, a molecule is what you get when those atoms bond together.

These might be the same elements, such as two oxygen atoms bonded together O2 , or it might be different atoms bonded together like water H2O. If three oxygen atoms bond together, you get the molecule ozone O3. Molecules can get complex, too. For example, the molecule acetone is made of carbon, hydrogen, and oxygen. Therefore, it has the chemical formula CH3 2O.

Why do atoms form molecules? The attraction between negatively charged electrons and positively charged protons in an atom give the atom its structure. The strong force holds neutrons and protons together in the nucleus. This force got its name because it is strong enough to overcome the force of the positively charged protons repelling each other. The number of electrons and protons in an atom determines its chemical properties.

Chemical properties include the specific ways that atoms and molecules react and the energy that they release or use in these reactions. One hundred million ,, hydrogen atoms put side-by-side equals about a centimeter. This means it would take about one hundred billion ,,, protons or neutrons put side-by-side to equal a centimeter.

This means that it would take one hundred trillion ,,,, electrons put side-by-side to equal a centimeter! The subatomic particles in an atom determine the properties of the atom. Some atoms exist naturally as neutral, or uncharged, atoms. An uncharged atom is electrically neutral because electrons and protons have opposite charges of equal sizes.

When the number of protons and electrons in an atom are same, the charges cancel out, or counteract each other. Every atom of a particular element has the same number of protons. The atomic number is equal to the number of protons in an element.

On the periodic table, the atomic number is usually given as the whole number above the symbol for the element see Fig. For example, hydrogen H has an atomic number of one 1. This means a hydrogen atom has one proton.

If a hydrogen atom is neutral, it must also have one electron. An oxygen atom O has an atomic number of eight 8. This means a neutral oxygen atom has eight protons and eight electrons.

The element Actium Ac has an atomic number of 89, so it has 89 protons and 89 electrons in a neutral atom. Table 2. Neutrons affect the mass of an atom and play a role in the stability of atoms. Unlike protons, the numbers of neutrons in elements varies. For example, most hydrogen atoms have no neutrons, but a few have one neutron, and some rare hydrogen atoms have two neutrons.

Most helium atoms have two neutrons, but some have three neutrons. The periodic table Fig. In Fig. In Figure 2. The periodic table has three prominent features. First, the periodic table is arranged in horizontal rows, which are called periods. There are seven periods. In Period 1 there are two elements, hydrogen H and helium He. The second and third periods both contain eight elements, the fourth and fifth periods contain 18 elements, and the sixth and seventh periods contain 32 elements.

Second, all of the elements are listed sequentially according to their atomic numbers. For example, in Figure 2. Third, the periodic table is arranged in columns of elements that react similarly. These columns are called groups. The group number is found at the top of the column. Groups 1—12 contain only metals, Groups 13—16 contain both metals and nonmetals, and Groups 17 and 18 contain only nonmetals.

One exception is hydrogen. Although technically a nonmetal, hydrogen has properties of both metals and nonmetals and is often placed in Group 1. The two long rows that are at the bottom of the periodic table are exceptions. The elements in each of these rows behave similarly, so are considered groups.