Agate is a mineral that appears banded due to impurities in its chemical composition. Agate is a variety of the mineral, quartz. Quartz is composed of silicon dioxide (SiO2), which is one part silicon for every two parts of oxygen. Which statement correctly describes the extended structure of quartz?

A.

alternating layers of silicon and oxygen atoms

B.

one layer of silicon atoms under two layers of oxygen atoms

C.

a pattern of repeating subunits of silicon dioxide

D.

a single molecule of silicon dioxide

assuming that your periodic table has eighteen columns, you should highlight   the four elements in the third column from the left of the table.

neutral atoms of elements after calcium contain d electrons. the energy of d orbitals of a particular main shell lies between the energy of the s and p orbitals of the next main shell. for example, electrons in the have energy higher than those in the orbital while lower than those of the orbital.

by the aufbau principle, electrons fill orbitals one at a time, starting from those of the lowest energy. the orbital is therefore filled right after orbitals and before orbitals.  

potassium has electron configuration and calcium . the s orbital of a main shell holds a maximum of two electrons. the next element would thus have the electron configuration and satisfy the requirements.

a neutral atom of the element contains three electrons on top of the most recent noble gas element. it should thus be placed in the third column of the periodic table. both scandium and yttrium would satisfy the conditions. an aufbau diagram indicates that the 4f orbital is filled before the 5d. however, it appears that exceptions exists for both lanthanum and actinium. neutral atoms of the two d-block elements also demonstrate the and should be highlighted as well.

the answer is b. dilution

a electronegativity decreases beacuse the size of nucleus is bigger.