The name atom comes from the Greek word-ἄτομος/átomos, α-τεμνω, This means that it will not be able to be divided further.
Relative to everyday experience, atoms are minuscule objects with proportionately tiny masses. Atoms can only be observed individually using special instruments such as the scanning tunneling microscope.
An atom consist of
1)Protons
2)Neutrons
3)Electrons
Words we must know!
Atom- the unit particle of an element
Proton number- The number protons in one atom of the element
Nucleon number- The number of nucleons, that is, the number if protons and neutrons in one atom of the element.
Element- A substance that consists of atoms all with the same proton number. It cannot be broken down into anything simpler by chemical means.
Isotopes- Different atoms of the same element
Facts about an atom
-The size of the nucleus is <>
-Electrons of an atom are of negligible mass and are always revolving around the nucleusat high speed.
- The mass is concentrated in the nucleus
Student to professor: If the nucleus contains positively charged protons, and like charges repel each other, why don't the protons repel each other and blow the nucleus apart?
Professor to student: Although the positive charges on the protons do tend to push them apart, there is another force at work. It is called the Strong Nuclear Force and it only operates over very small distances - about 10-15 metres, which is about the size of the atomic nucleus. When protons are roughly this distance apart, the Strong Nuclear Force takes over and pulls the protons (and neutrons, if there are any) together and holds them tightly.
Myths
Facts
The electron shells are orbits, like rail track on which the electrons move.
The electron shells represent energy levels rather than physical orbits.
The mass of a proton and a neutron is 1g each.
The mass of a proton and a neutron are about 1.6X10-24, which means they are very light. The relative mass is 1. That is, when we compare the mass of proton and neutron, they are roughly the same.
An atom is a solid sphere.
The size of a neutron is extremely small compared to the entire size of the atom. In fact, most of the atom consists of empty space.
The isotopes have different chemical properties.
Isotopes are the atoms of the same element. They have similar chemical properties. Elements are defined by the number of protons and the number of electrons. Since isotopes only have a different number of neutrons, their chemical properties are the same.
Rutherford’s experiment.
Rutherford did an experiment to determine what atoms were like. He fired a beam of particles at a thin gold foil, tracking them using a detector. However, he discovered that most of the particles went straight through the foil, while some were deflected at an angle and some even bounced straight back. This showed that most of the particles passed through empty space but that some were being deflected by a small point charge.
Monday, September 21, 2009 @ 7:27 AM .
BY JOY AND NATASHA
ATOMIC STRUCTURE
An atom is- the smallest particle
The name atom comes from the Greek word-ἄτομος/átomos, α-τεμνω, This means that it will not be able to be divided further.
Relative to everyday experience, atoms are minuscule objects with proportionately tiny masses. Atoms can only be observed individually using special instruments such as the scanning tunneling microscope.
An atom consist of
1)Protons
2)Neutrons
3)Electrons
Words we must know!
Atom- the unit particle of an element
Proton number- The number protons in one atom of the element
Nucleon number- The number of nucleons, that is, the number if protons and neutrons in one atom of the element.
Element- A substance that consists of atoms all with the same proton number. It cannot be broken down into anything simpler by chemical means.
Isotopes- Different atoms of the same element
Facts about an atom
-The size of the nucleus is <>
-Electrons of an atom are of negligible mass and are always revolving around the nucleusat high speed.
- The mass is concentrated in the nucleus
Student to professor: If the nucleus contains positively charged protons, and like charges repel each other, why don't the protons repel each other and blow the nucleus apart?
Professor to student: Although the positive charges on the protons do tend to push them apart, there is another force at work. It is called the Strong Nuclear Force and it only operates over very small distances - about 10-15 metres, which is about the size of the atomic nucleus. When protons are roughly this distance apart, the Strong Nuclear Force takes over and pulls the protons (and neutrons, if there are any) together and holds them tightly.
Myths
Facts
The electron shells are orbits, like rail track on which the electrons move.
The electron shells represent energy levels rather than physical orbits.
The mass of a proton and a neutron is 1g each.
The mass of a proton and a neutron are about 1.6X10-24, which means they are very light. The relative mass is 1. That is, when we compare the mass of proton and neutron, they are roughly the same.
An atom is a solid sphere.
The size of a neutron is extremely small compared to the entire size of the atom. In fact, most of the atom consists of empty space.
The isotopes have different chemical properties.
Isotopes are the atoms of the same element. They have similar chemical properties. Elements are defined by the number of protons and the number of electrons. Since isotopes only have a different number of neutrons, their chemical properties are the same.
Rutherford’s experiment.
Rutherford did an experiment to determine what atoms were like. He fired a beam of particles at a thin gold foil, tracking them using a detector. However, he discovered that most of the particles went straight through the foil, while some were deflected at an angle and some even bounced straight back. This showed that most of the particles passed through empty space but that some were being deflected by a small point charge.
