Atoms Science

37. What determine the mass number of an atom?

An isotope?

38. How are isotopes named?

Hydrogen atoms with one neutron are the isotope known as deuterium, and those with two neutrons are the isotope named tritium. For most elements other than hydrogen, isotopes are named for their mass number, which is the number of protons plus neutrons.

46. What are the properties of metals on the Periodic Table?

I am a ___________________ if I am dull and brittle. I am a _______________________ if I can be pulled into wires easily and conduct electricity. If I can be hammered and bent into shape I am a ____________________

57. What are the properties of the Nitrogen Group?

N, P, As, Sb, Bi. 2 non-metals, 2 metalloids, 2 metals. 5 valence electrons. -3 ion charge. varied reactivity. all but nitrgogen are solid at room temp.

58. What are the properties of the Oxygen Group?

O, S, Se, Te, Po. 3 non-metals, metalloid, 1 metal. -2 ion charge. 6 valence electrons. reactive. all but oxygen are solids at room temp.

Where is the nucleus found in the atom?

The nucleus is a small, dense region at the center of the atom. It consists of positive protons and neutral neutrons, so it has an overall positive charge. The nucleus is just a tiny part of the atom, but it contains virtually all of the atom's mass. What is the nucleus? The central core of the atom that has protons and neutrons. Part of the atom is has the most mass.

What is Thomsons "plum-pudding model"?

The plum pudding model demonstrated that atoms are mostly empty space. Plum pudding model was proposed in 1904. It is negatively charged electrons (raisins or blue berries) are surrounded by a positively charged "pudding" (or muffing). The plum-pudding model is JJ Thomson atomic model and it showed most of the tiny particles went straight through the gold foil, with a small number being deflected. In order to explain this, atoms must be considered mostly empty space, with a tiny part made of highly dense matter. Thomson thought that electrons were mixed throughout an atom, like plums in a pudding (or we might call it the chocolate chip ice cream model).

31. What is the amu for the proton, neutron, and electron?

The proton weighs 1.0073 amu and the neutron weighs 1.0087 amu. Mass of electron is 0.000548597 a.m.u. or 9.1 x 10-31 kg.

What are the three classes of elements stated on the Periodic Table?

The three main classes of elements are metals on the left side, metalloids on the staircase, and nonmetals on the right hand side.

41. What kind of pattern did Mendeleev find when looking at the elements?

A regular repeated pattern; When he arranged the elements in order of increasing atomic mass

56. What are the properties of the Carbon Group?

C, Si, Ge, Sn, Pb. 1 non-metal, 2 metalloids, 3 metals. +/- 4 ion charge. 4 valence electrons. varied reactivity. solids at room temp.

19. What role did Schrodinger and Heisenberg in developing the atomic theory?

Electrons do not travel in orbits, but in regions called electron clouds. Austrian physicist Erwin Schrodinger and German physicist Werner Heisenberg showed one aspect of the Bohr-Model was incorrect. They proved that electrons do not travel in set, predictable paths. The current atomic theory states that the electrons paths are not definite, but there are regions within the atom where the electrons are likely to be. These likely regions are known as orbitals and together form the electron cloud. This model is known as the electron cloud model. We now know that electrons move so quickly within the cloud that it is like they are everywhere at once.

Describe Thomson's Cathode-Ray Tube Experiment?

. Almost all gas was removed from the glass tube 2. An invisible beam was produced when the tube was connected to a source of electrical energy. 3. Metal plates could be charged to change the path of the beam. 4. When the plates were not charged, the beam made a glowing spot at the end of the tube. 5. When the plates were charged, the beam made a glowing spot down lower at the end of the tube after being pulled toward the positively charged plate.

What is the size of an atom?

3 x 10 (-8power) cm = .00000003 cm; 3 hundred millionths cm

54. What are the properties of the Transition Metals?

30 members. Excellent conductors of heat and electricity. 1 or 2 valence electrons. solids at room temp. high density. high melting points. more like friends ;); Lustrous:Shiny; Thermal:Heat; Ductile:Can be drawn into a wire; Malleable:Can be hammered in to shape; Sonorous:"Dings" when struck; Dense:Thick; Be, Mg, Ca, Sr, Ba, Ra. Harder and denser than alkali metals. Highly reactive. Never found in free nature. 2 valence electrons, generally have positive ions. +2 ion charge

What is the Atomic Theory Timeline?

440 B.C. Demoscritus 1803 Dalton 1897 Thomson 1909/1911 Rutherford 1913 Bohr 20th Century (1926) Schrodinger & Heisenberg

47. What are the properties of non-metals on the Periodic Table?

? I am a ___________________ if I can be a solid, liquid, or maybe a gas at room temperature and I am non-conductive. I am a ___________________ if I am dull and brittle

34. What is an isotope?

? Isotopes are defined as atoms with the same number of protons, but different numbers of neutrons. Atoms of isotopes are the same element because they have the same number of protons. Atoms of isotopes have different masses because they have a different number of neutrons. Isotopes of an atom share most of the same physical and chemical properties. Isotopes of an element can be identified by their mas number.The mass number is the sum of the protons and neutrons found in the nucleus.The atomic mass of an element is an average of the masses of all natural isotopes of an atom. To calculate the number of neutrons in an atom,

32. How do the atoms of different elements differ?

An atom is the building block of matter

36. What are the properties of isotopes?

An isotope contains 11 protons, 10 electrons, and 12 neutrons. They different masses because they differ in the number of neutrons. They have the same atomic number and same number protons in the nucleus. Elements with the same atomic number but a different mass number are defined as "Isotopes". Chemical properties of isotopes of any element are almost identical. The exception to this case is the isotopes of hydrogen because the numbers of neutrons have a major effect on the size of the nucleus of a hydrogen atom. An isotope is an atom that has a different number of neutrons than the atom in its most common form. For instance, the most common form of carbon is carbon-12 with 6 protons and 6 neutrons. However, carbon-14 also exists with 6 protons and 8 neutrons.

How did Aristotle disagree with Democritus Theory?

Aristotle (AIR·ih·staht'l), another Greek philosopher, disagreed. He did not believe that such a particle could make up all substances found in nature.​ Aristotle vehemently opposed the Atomic theory developed by Democritus. He did not believe that such an indivisible particle existed. He disagreed with Democritus's idea that you would never end up with a particle that could not be cut.

What does the word atomos mean?

Around 400 BCE, a Greek philosopher named Democritu (dih·MAHK·rih·tuhs) thought that you would eventually end up with a particle that could not be cut. He called this particle atomos, a Greek word meaning "not able to be divided." Democritus reasoned that if you continued to cut the stone into smaller and smaller pieces, at some point you would reach a piece so tiny that it could no longer be divided. Democritus called these infinitesimally small pieces of matter atomos, meaning "indivisible."

What is Democritius's role in Atomic Theory?

Around 440 BCE, Greek philosopher Democritus first proposed the idea of a particle that could not be cut any smaller. He called this particle atomos, meaning uncuttable or indivisible. Democritus expanded this theory to state that matter was composed of small particles called "atoms" that could be divided no further. Democritus's model stated that matter consists of invisible particles called atoms and a void (empty space). He stated that atoms are indestructible and unchangeable.

What is an atom?

Atoms are small particles that are made up of even smaller particles, which determine the properties of the atom. The basic particle from which all elements are made. Made up of a nucleus with protons and neutrons and surrounded by electrons. Atoms are neutral and The number of protons is always the same as the number or electrons in an atom. If an atom loses or gains electrons it is no longer an atom. It is an ion. - If an atom loses an electron it becomes a positive ion (cation) - If it gains an electron, it becomes a negative ion (anion).

35. How does an isotope differ from an atom?

Atoms of the same element with the same number of protons, but different numbers of neutrons

What is the Modern Atomic Theory?

Electron Cloud Model; Electrons do NOT travel in definite paths as Bohr suggested, the exact path of an electron cannot be predicted. There are regions inside the atom where electrons are likely to be found - Electron Clouds.

59. What are the properties of the Halogens group?

F, Cl, Br, I, At. all non-metals. -1 ion charge. 7 valence electrons. Poor conductors of electricity. violent reactions with alkali metals to form salts. never free in nature (always combined)

What experiment Dalton he do to develop his theory?

Fill in laterHe experimented with gases, oxygen and hydrogen. (Please ask the teacher about this one?)

17. What did Rutherford conclude about the size of the nucleus?

He calculated that the diameter of the nucleus was 100,000 times SMALLER than the diameter of the gold atom.

What was the experiment that JJ Thomson used to come up with his Theory?

He discovered that a positively charged plate attracted the beam. He concluded that the beam was made of particles that have negative electric charges. He also concluded that these negatively charged particles are present in every kind of atom. (negatively charged particles are called ELECTRONS today. He used a Cathode-Ray Tube.

43. What did Mendeleev determine about missing (undiscovered) elements?

He was also able to work out the atomic mass of the missing elements, and so predict their properties. And when they were discovered, Mendeleev turned out to be right. For example, he predicted the properties of an undiscovered element that should fit below aluminium in his table.

60. What are the properties of the Noble Gas group?

He, Ne, Ar, Kr, Xe, Rn. non-metals. 8 valence electrons. +/- 0 ion charge. not reactive. colorless odorless gases at room temp.

What was JJ Thomson's contribution to the Atomic Theory?

In 1897, J.J. Thomson, a British scientist, showed that a part of Dalton's Atomic Theory was incorrect. Thomson showed that there were even smaller particles inside the atom, disproving Dalton's idea that atoms could not be divided into smaller pets. Thomson actually had discovered the presence of a negative particle inside the atom. This particle was called an electron. Thomson believed that electrons were distributed throughout the whole atom.

What is Ernest Rutherford's role in develop his theory?

In 1909, Ernest Rutherford conducted an experiment to study the parts of the atom. His experiment suggested that atoms have a nucleus—a small, dense center that has a positive charge and is surrounded by moving electrons. Rutherford later found that the nucleus is made up of smaller particles. He called the positively charged particles in the nucleus protons. ​

What is the nucleus?

In 1909, Ernest Rutherford conducted an experiment to study the parts of the atom. His experiment suggested that atoms have a nucleus—a small, dense center that has a positive charge and is surrounded by moving electrons. Where is it found? Center of the atom.

14. What was Rutherford contribution to the Atomic Theory?

In 1911, he was the first to discover that atoms have a small charged nucleus surrounded by largely empty space, and are circled by tiny electrons, which became known as the Rutherford model (or planetary model) of the atom. He is also credited with the discovery of the proton in 1919, and hypothesized the existence of the neutron. He was awarded the Nobel Prize in Chemistry in 1908 "for his investigations into the disintegration of the elements, and the chemistry of radioactive substances".

51. How are elements on the periodic table represented?

In the typical periodic table, each element is listed by its element symbol and atomic number. For example, "H" denotes hydrogen, "Li" denotes lithium, and so on. Most elements are represented by the first letter or first two letters of their English name, but there are some exceptions. In the typical periodic table, each element is listed by its element symbol and atomic number. For example, "H" denotes hydrogen, "Li" denotes lithium, and so on. Most elements are represented by the first letter or first two letters of their English name, but there are some exceptions.

What are electrons?

J. J. Thomson's experiments provided evidence that atoms are made up of even smaller particles. He found particles within the atom that have a negative charge. These negatively charged particles later became known as electrons. Electrons are negatively charged subatomic particles that are found outside of the nucleus in the electron cloud. They are least massive of any of the subatomic particles (Particles within the atom). The units for mass of subatomic particles are atomic mass units (amu).

What was Dalton's atomic theory?

John Dalton, a British chemist and teacher, first proposed his atomic theory in 1803. Dalton's Atomic Theory 1. all Substances are made of atoms 2. atoms are small particles that cannot be created, destroyed, or divided 3. atoms of the same element are exactly alike 4. atoms join with other atoms to make new substances

What experiment did Rutherford use to develop his theory?

Name and describe Rutherford's experiment. "Shooting Gallery" or Gold Foil Experiment. In 1909, Ernest Rutherford, a student of Thomson's, further revised the atomic theory. Rutherford proposed that the atom was mostly empty space with a tiny part made of highly dense matter. He believed that in the center of the atom was an extremely dense, positively charged center which he called the nucleus. He aimed a beam of small, positively charged particles at a thin sheet of gold foil. He put a special coating behind the foil so the coating glowed when hit by the positively charged particles. He could then see where the particles went after hitting the gold.

53. What are the properties of Alkaline-earth metals?

Properties of alkaline Earth metals include a) gray or silver color. b) low density. c) softness. a) barium. Calcuim and Magnisium

42. What does periodic mean?

Relating to the periodic table of elements or the patter of the chemical properties that underlines it

40. Who is Dmitri Menedeleev?

Russian chemist who developed the periodic classification of the elements. He arranged the elements into rows in order of increasing mass so that elements with similar properties were in the same column.

What was Rutherford's Atomic Theory?

Rutherford's theory of the atom was that in the center of the atom is a tiny, extremely dense, positively charged part called the nucleus. Because like charges repel, He reasoned that positively charged particles that passed close by the nucleus were pushed away by the positive charges in the nucleus. His model of the atom had electons surrounding the nucleus at a distance.

44. What does the periodic law state?

States that when the elements are arranged by increasing atomic number, there is a periodic repetition of their properties.

55. What are the properties of the Boron Group?

The commonest property of the group is that each one of the elements has three electrons in the outer shell of their nuclear structure; B, Al, Ga, In, Tl. 1 metalloid, 5 metals, 0 non-metals. 3 valence elecrons. +3 ion charge. reactive. solid at room temp.

What about (Dalton) this theory ended up being incorrect?

The indivisibility of an atom was proved wrong: an atom can be further subdivided into protons, neutrons and electrons. However an atom is the smallest particle that takes part in chemical reactions. According to Dalton, the atoms of same element are similar in all respects; Dalton was wrong about atoms being indivisible (they are made up of subatomic p+, e-, and n+/-) about all atoms of a given element having identical properties (the masses of isotopes differ)

30. What is atomic mass?

The number of protons and neutrons combined together is called atomic mass or mass number. The average mass of all the isotopes of an element

33. What is used to determine the atomic number?

The number of protons in the nucleus of an atom determines an element's atomic number. In other words, each element has a unique number that identifies how many protons are in one atom of that element. For example, all hydrogen atoms, and only hydrogen atoms, contain one proton and have an atomic number of 1. (What determines the identity of an atom? The atomic number)

52. What are the properties of Alkali Metals?

They all have on electron in their outer shell; - they are very reactive. -Low melting and boiling points (decreases as you go down the group) - attraction between electrons and nucleus is weaker so atom's bonds can be more easily broken- compared to other metals - Low density which increases as you go down the group - large atomic radius compared to little atomic mass - lithium, sodium and potassium float on water - Very soft - it can be cut with a knife (loosely packed together atom); Li, Na, K, Rb, Cs, and Fr. All metals, softer and less dense. Can be cut with a knife. Most reactive of the metals. Always coupled with another element. cant be exposed to water. 1 valence electron always forms positive ions. Can be found based on flame tests and the colors they produce. + ion charge.

39. How do you calculate atomic mass?

To calculate the atomic mass of a single atom of an element, add up the mass of protons and neutrons.

50. What does the group on the periodic table represent?

a column on the periodic table, also known as a chemical family since elements in groups share similar chemical properties . Elements that occupy the same column on the periodic table (called a "group") have identical valance electron configurations and consequently behave in a similar fashion chemically. For instance, all the group 18 elements are inert gases. The periodic table also has a special name for its vertical columns. Each column is called a group. The elements in each group have the same number of electrons in the outer orbital. Those outer electrons are also called valence electrons; The vertical columns on the periodic table have special names, too. They are called groups or families. Remember that all elements in a group or family have similar chemical properties (except H in some cases). Each group is represented by a Roman numeral and letter.

What are electron clouds?

a region around the nucleus of an atom where electrons are likely to be found. In the current atomic theory, electrons do not move in circular paths around the nucleus as Bohr thought. Instead, the current theory suggests that electrons move within an area around the nucleus called the electron cloud.

49. What does the period on the periodic table represent?

a row on the periodic table. A period number is the number that is given to a group of elements across the periodic table that have made a round from completing its outer electron shell. A period in the periodic table is a horizontal row. All elements in a row have the same number of electron shells. Each next element in a period has one more proton and is less metallic than its predecessor.

28. What kind of charge do neutrons have?

a small particle in the nucleus of the atom, with no electrical charge. They do not carry a charge.

What kind of charge do electrons have?

a tiny, negatively charged particle that moves around the outside of the nucleus of an atom

29. What is an atomic mass unit (amu)?

one twelfth the mass of a carbon-12 atom.

What are the parts of an atom?

protons, neutrons, and electrons are found within the atom

48. What does the Chemical Symbol represent on the Periodic Table?

representing an element.

What kind of charge do protons have?

small, positively charged particle that is found in the nucleus of an atom.