able to appear because an excited electron was unstable and had to fall back to a more stable energy level‚ creating energy in the form of light. However‚ to understand this‚ one must understand what causes an electron to be excited. So from the very beginning‚ a person named Max Plank proposed a theory that energy is emitted and absorbed in quantities called “quanta.” Einstein then came along and said that light contained quanta energy called “photons.” Electrons that are present in atoms are on
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light hits it. Classical mechanics says that electrons will be emitted from a metal by light waves with any frequency as long as the intensity of the light is strong enough‚ and even if it is weak over a long enough period of time electrons will eventually be emitted. The theory was proved incorrect after experiments showed that light under certain frequencies did not produce the photoelectric effect on the metal‚ which meant that the emitting of electrons is related not to intensity but the waves
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various types of nuclear radiation. There is more than one type of particle accelerator; they come in two basic types: • Linear • Circular Linear Accelerators The linear accelerator‚ or linac‚ uses microwave technology to accelerate electrons in a part of the accelerator called the "wave guide". Particles pass through a line of hollow metal tubes enclosed in an evacuated cylinder. Within a hollow conductor there is no electric field so a charged particle travels at constant speed inside
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or gamma d. charged atoms or molecules that have gained or lost electrons. ____ 2. Sodium has eleven protons. How many electrons does it have in its outermost shell? a. one b. two c. four d. six ____ 3. Chlorine‚ with an atomic number of 17‚ would be expected to have ___ electrons in its outer shell. a. five b. seven c. three d. one ____ 4. The negatively charged subatomic particle is the a. electron. b. proton. c. neutron. d. nucleus. ____ 5. Isotopes
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upon the structure of the atom. Before Rutherford‚ there was a man named Joseph John Thomson who proposed the structure of the atom. He stated that the electrons of the atoms are actually inside the atom‚ and the atom itself is positively charged‚ like a “raisin pudding”. The electrons are scattered all around the atom. He stated that the electrons and the positively charged material cancel each other‚ making it stable. The structure of the atom‚ proposed by Thomson. (J.J Thomson Plum Pudding Model
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electron neutron proton Electricity is generated from the motion of tiny charged atomic particles called electrons and protons. Electricity is the flow of electrical power or charge. >> found out that amber when rubbed with fur can attract light materials such as straws and feathers. >> described the electrification of many substances and coined the term “electricity” from the Greek word for “amber”. >> Father of Modern Electricity defined as the study of electricity at rest. the
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heart of our understanding of the structure of atom. New Zealand scientist Ernerst Rutherford was the first to show that the atom is the building block of all matter that consists of a positively charged nucleus surrounded by tiny negatively charged electrons. The extraordinary achievements of these scientists have been instrumental development of chemistry over the past century. Today‚ we take the existence of atoms for granted. We can explain many aspects of the structure of the atom and in fact‚ current
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protons‚ neutrons and electrons are there in 3+ ion? 2. Write down the electronic configuration of (a) Si (atomic no. 14) (b) Sc (atomic no. 21) (c) Co (atomic no. 27) 3. Which of the following ions contains an unpaired electron? A calcium ion B copper(II) ion C potassium ion D titanium(IV) ion 4. Some isotopes are unstable and decompose naturally. In one type of decomposition‚ a neutron in the nucleus decomposes to form a proton‚ which is retained in the nucleus‚ and an electron‚ which is expelled
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particles that make up atoms are protons‚ neutrons‚ and electrons. 2. Why do all isotopes of an element have the same chemical properties? In what way do isotopes of an element differ? An isotope has the same number of protons but a different number of neutrons in the nucleus. 3. What is a covalent bond? An ionic bond? An ionic bond is formed when one or more electrons are transferred from one atom to another. Covalent bond forms when electrons are shared between atoms. 4. What is a compound
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neutrons 32 60 28 32 number of orbital electrons 28 28 28 32 2 A nucleus of bohrium x Bh decays to mendelevium y emissions. bohrium x Bh → dubnium + α y → lawrencium + α 255 Md 101 by a sequence of three α-particle → mendelevium 255 Md + α 101 How many neutrons are there in a nucleus of x Bh? y A B C D 267 261 160 154 3 Which set of radioactive emissions corresponds to the descriptions given in the table headings? high-speed electrons A B C D α α β β high-speed helium nuclei
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