Answer: Elements in Group 2
Explanation: The periodic table was arranged by Dmitri Mendeleev specifically around similarites in their chemical behaviors. He found that as atomic number increases, at some point an element starts to react in a manner similar to a previous one. When that happened, he would place the larger element under the smaller one, and eventually noticed a periodicity in the table. Elements in a column (Groups) had similiar chemical properties. We know today that these similarities are due to the electron configuration, and that these configurations repeat themselves. He left gaps in the table when he could find an existing element with properties similar to others in that group. I big leap of faith, but it worked. Elements for those missing boxes were eventually discovered.
Answer:
454.3 g.
Explanation:
1.0 mol of CaO liberates → – 64.8 kJ.
??? mol of CaO liberates → - 525 kJ.
∴ The no. of moles needed = (1.0 mol)(- 525 kJ)/(- 64.8 kJ) = 8.1 mol.
<em>∴ The no. of grams of CaO needed = no. of moles x molar mass</em> = (8.1 mol)(56.077 g/mol) = <em>454.3 g.</em>
Answer:
The International Bottled Water Association (IBWA), Alexandria, Va., and Beverage Marketing Corporation (BMC), New York, recently released 2015 bottled water statistics showing that Americans' consumption of bottled water increased by 7.9 percent and bottled water sales were up 8.9 percent from the previous year.
Explanation:
Ionization energy increases from left to right because the left wants to lose elctrons and the right wants to gain electron
As you go a group it is easier lose lose because the electrons are farther away from the nucleus and there is less attraction from the positive charges.
It should be 3p3. the p level can hold 6 electrons
Rubidium group 1, 1 valence electrons very reactive
Mg2,2 very reactive
Al 3, 3 reactive
