One of the basic building blocks of matter, which cannot be broken down by chemical means is an element.
The first chemical element is hydrogen (atomic number is 1) and the last is oganesson (atomic number is 118).
Elements are scheduled in Periodic table, ordered by their atomic number.
Other example, krypton is a chemical element with symbol Kr and atomic number 36.
Krypton has 36 electron and 36. It is noble gas (group 18).
Noble gases are in group 18: helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe) and radon (Rn). They have very low chemical reactivity.
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Answer:
See below
Explanation:
<u> Name </u> <u>Formula </u> <u> Major species </u> <u> </u>
Zinc iodide ZnI₂ H₂O(ℓ), I⁻(aq), Zn²⁺(aq),
Nitrogen(I) oxide N₂O H₂O(ℓ), N₂O(aq)
Sodium nitrite NaNO₂ H₂O(ℓ), Na⁺(aq), NO₂⁻(aq)
Glucose C₆H₁₂O₆ H₂O(ℓ), C₆H₁₂O₆(aq)
Nickel(II) iodide NiI₂ H₂O(ℓ), I⁻(aq), Ni²⁺(aq)
- Glucose and nitrogen(I) oxide are covalent compounds. They do not dissociate in solution.
- The compounds containing metals are ionic. They produce ions in solution.
- ZnI₂ and NiI₂ produce twice as many iodide ions as metal ions.
Answer: The mole ratio of hydrogen to nitrogen is 3 mole: 1 mole, 3:1
Explanation:
•Mole ratios are determined using the coefficients of the substances in the balanced chemical equation. •Each coefficient represents the number of mole of each substance in the chemical reaction.
•The mole ratio can be determined by first writing out a balanced chemical equation for the reaction.
For this reaction the balanced chemical equation is
N2(g) + 3H2(g) ----> 2NH3(g)
1mol:3mol : 2mol
From the equation we can see that 1 mole of N2(g) reacts with 3 moles of H2(g) or 3 moles of H2(g) react with 1 mole of N2(g) to produce 2 moles of NH3(g).
Therefore, the mole ratio of hydrogen to nitrogen is 3 mole: 1 mole, 3:1
Answer:
The immune system responds to antigens by producing cells that directly attack the pathogen, or by producing special proteins called antibodies. Antibodies attach to an antigen and attract cells that will engulf and destroy the pathogen. The main cells of the immune system are lymphocytes known as B cells and T cells.
