science atomic structure

• What is the symbol for Carbon?


  C
• What is the symbol for Hydrogen?


  H
• What are the atomic numbers of the first 20 elements?

  1. Hydrogen - 1
  2. Helium - 2
  3. Lithium - 3
  4. Beryllium - 4
  5. Boron - 5
  6. Carbon - 6
  7. Nitrogen - 7
  8. Oxygen - 8
  9. Fluorine - 9
  10. Neon - 10
  11. Sodium - 11
  12. Magnesium - 12
  13. Aluminum - 13
  14. Silicon - 14
  15. Phosphorus - 15
  16. Sulfur - 16
  17. Chlorine - 17
  18. Argon - 18
  19. Potassium - 19
  20. Calcium - 20
• What is the significance of atomic numbers in elements?

  • Atomic number indicates the number of protons.
  • Determines the element's identity.
  • Influences chemical properties and behavior.
• What is electron configuration?

  The arrangement of electrons in atoms
• What is the maximum number of electrons in the first shell?

  2 electrons
• What is the maximum number of electrons in the second shell?

  8 electrons
• What is the maximum number of electrons in the third shell?

  8 electrons
• What is the electronic arrangement of lithium and potassium?

  • Both have 1 electron in their outer shell
  • Their outer shells are not full
• What do helium and argon have in common regarding electronic arrangement?

  • Both have full outer shells
  • They are noble gases
• Why do atoms have no charge?

  Number of protons equals number of electrons
• What are isotopes?

  Atoms with the same protons but different neutrons
• Why do isotopes have similar reactions?

  They have the same number of protons
• How do isotopes differ in physical properties?

  Neutrons affect density and boiling point
• What is the average relative atomic mass of chlorine calculated using Method 1?

  35.5
• What is the atomic structure of an atom?

  Consists of a nucleus and electrons in shells
• What are the key ideas of atomic theory from various scientists?

  • Democritus: Atoms are indivisible
  • Dalton: Atoms combine in whole number ratios
  • Thomson: Plum pudding model
  • Rutherford: Nucleus contains most mass
  • Bohr: Electrons orbit in fixed energy levels
  • Chadwick: Neutrons exist in the nucleus
• How are elements arranged in the periodic table?

  According to increasing atomic number
• What did Mendeleev do to improve the periodic table?

  Left gaps for undiscovered elements
• What are the properties of Group 1 metals?

  • Soft and shiny
  • Low density and low melting points
  • React vigorously with water
• What happens when potassium reacts with water?

  It produces potassium hydroxide and hydrogen
• Why is rubidium more reactive than potassium?

  It has more shells, further from nucleus
• What are the characteristics of halogens?

  • 7 electrons in outer shell
  • Reactivity decreases down the group
  • Important uses, e.g., iodine as antiseptic
• What is displacement in halogen reactions?

  A more reactive halogen replaces a less reactive one
• What is the state of fluorine at room temperature?

  Gas
• What is the color of bromine at room temperature?

  Pale yellow
• What is the state of iodine at room temperature?

  Solid
• What happens to reactivity as you go down Group 7?

  Reactivity decreases
• Why are halogens very reactive?

  They need one electron to gain a full shell
• What are the states of halogens at room temperature?

  • Fluorine: gas
  • Chlorine: gas
  • Bromine: liquid
  • Iodine: solid
• What is iodine used for?

  As an antiseptic to kill bacteria
• What occurs when a halogen is added to a less reactive halogen compound?

  It reacts and forms a new compound
• What is the term for the reaction where a more reactive halogen displaces a less reactive one?

  Displacement reaction
• What is the chemical equation for fluorine reacting with sodium?

  Fluorine + Sodium → Sodium fluoride
• What is the chemical equation for bromine reacting with sodium?

  Bromine + Sodium → Sodium bromide
• What is the state and color of chlorine at room temperature?

  Gas, pale green
• What is the state and color of bromine at room temperature?

  Liquid, dark red
• What is the state and color of iodine at room temperature?

  Solid, grey-black
• What are the properties of Group 0 elements?

  • Unreactive
  • Gas state at room temperature
  • Full outer electron shell
• What happens to boiling points in Group 0 as you move down the group?

  Boiling points increase