The best answer is the isotope of strontium which is strontium-85. It has a half-life of about 64 days. The metal strontioum has four stable, naturally occurring isotopes which includes 84Sr (0.56%), 86Sr (9.86%), 87Sr (7.0%) and 88Sr (82.58%).
<span>Express the answer in scientific notation and with the correct number of significant figures:
(6.32 x 10-4) ÷ 12.64
5.00 x 10^-5</span>
Answer:
The next high tide will happen at 6 pm.
Explanation:
The rotation of the Earth and the translation movement of the Moon (ie the Moon's movement around the Earth), in addition to the gravitational force, contribute to the formation of the tides. The high tide will occur on the face of the Earth which is facing / facing the Moon; the low tide will occur on the faces that are forming approximately an angle of 90 ° with respect to the Moon.
There are usually two periods of high tide and two periods of low tide over a day. The interval between high tide and low tide is approximately 6 hours.
Besides the gravitational force exerted by the Moon, the tide is also influenced by the gravitational force that the Sun exerts on the Earth. The influence of the Sun is smaller due to its distance, but it can also be noticed depending on the phase of the Moon.
Answer: The Lattice energy is the energy required to separate an ionic solid into its component gaseous ions <em>or</em>
It is the energy released when gaseous ions combine to form an ionic solid.
Explanation:
The lattice energy depends on the ionization energies and electron affinities of atoms involved in the formation of the compound. The ionization energies and electron affinities also depends on the ionic radius and charges of the ions involved. As the ionic radius for cations <em>increases</em> down the groups, ionization energy <em>decreases</em>, whereas, as ionic radii <em>decreases</em> across the periods , ionization energy <em>increases</em>. The trend observed for anions is that as ionic radii <em>increase </em>down the groups, electron affinity <em>decreases. </em>Across the period, as ionic radii <em>increases</em> electron affinity <em>increases</em>. Also, as the charge on the ion <em>increases,</em> it leads to an <em>increase</em> in energy requirement/content.
Therefore, for compounds formed from cations and anions in the same period, the highest charged cation and anion will have the highest lattice energy. For example, among the following compounds: Al2O3 (aluminium oxide), AlCl3 (aluminium chloride), MgO, MgCl2 (magnesium chloride), NaCl, Na2O (sodium oxide); Al2O3(aluminium oxide) will have the highest lattice energy, thus will be hardest to break apart because its ions have the highest charge.
